are all the rectangles faces the same size

Answers

Answer 1
if you mean cuboid then no and if you mean rectangle but sides not faces then yes
Answer 2

Answer:

A rectangle is a 2 dimensional figure, it is in a plane, so it has two faces, and yes, they are equals.


Related Questions

Ares is making 14 jars of honey peanut butter. He wants to use 45 milliliter (ML) of honey in each jar. How much honey (in ML) will ares use in all?

Answers

Answer:

630 milliliters.

Step-by-step explanation:

The statement tells us that the final product is 14 jars of honey peanut butter and that in each jar use 45 mliliters of honey. This means that to know the total honey to be used, the required quantity for each jar must be multiplied by the total number of jars, that is:

14 * 45 = 630

Which means that he would spend a total of 630 milliliters.

Step-by-step explanation:

Ares uses 630 ml of honey, because 14×45=630

A multiple-choice standard test contains total of 25 questions, each with four answers. Assume that a student just guesses on each question and all questions are answered independently. (a) What is the probability that the student answers more than 20 questions correctly

Answers

Answer:

[tex]P(x>20)=9.67*10^{-10}[/tex]

Step-by-step explanation:

If we call x the number of correct answers, we can said that P(x) follows a Binomial distribution, because we have 25 questions that are identical and independent events with a probability of 1/4 to success and a probability of 3/4 to fail.

So, the probability can be calculated as:

[tex]P(x)=nCx*p^{x}*q^{n-x}=25Cx*0.25^{x}*0.75^{25-x}[/tex]

Where n is 25 questions, p is the probability to success or 0.25 and q is the probability to fail or 0.75.

Additionally, [tex]25Cx=\frac{25!}{x!(25-x)!}[/tex]

So, the probability that the student answers more than 20 questions correctly is equal to:

[tex]P(x>20)=P(21)+P(22)+P(23)+P(24)+P(25)[/tex]

Where, for example, P(21) is equal to:

[tex]P(21)=25C21*0.25^{21}*0.75^{25-21}=9.1*10^{-10}[/tex]

Finally, P(x>20) is equal to:

[tex]P(x>20)=9.67*10^{-10}[/tex]

Given that f(x) = x² + 4x, evaluate f(-2).

Answers

Answer:

-4

Step-by-step explanation:

Score: 4 of 8 pts
TA
23.1.59
A ball is thrown upward and outward from a height of 5 feet. The height of the ball, f(x), in feet, can be mo
f(x) = -0.2x² +2.1x+5
where x is the ball's horizontal distance, in feet from where it was thrown. Use this model to solve parts (
a. What is the maximum height of the ball and how far from where it was thrown does this occur?
The maximum height is feet, which occurs feet from the point of release
(Round to the nearest tenth as needed.)​

Answers

Answer:

  10.5 ft high

  5.3 ft horizontally

Step-by-step explanation:

The equation can be written in vertex form to answer these questions.

  f(x) = -0.2(x² -10.5x) +5

  f(x) = -0.2(x² -10.5x +5.25²) +5 +0.2(5.25²)

  f(x) = -0.2(x -5.25)² +10.5125

The vertex of the travel path is (5.25, 10.5125).

The maximum height is 10.5 feet, which occurs 5.3 feet (horizontally) from the point of release.

Help needed please!!!!!!!!
Olivia recorded the prices of 10 paperback books and 10 hard cover books. Her data is shown.
Paperback: $6.99, $7.49, $12.99, $9.99, $5.99, $8.99, $9.99, $10.00, $3.99, $4.99
Mean: 8.14
Hard cover: $9.99, $12.99, $34.99, $16.99, $15.00, $19.99, $9.99, $10.99, $18.99, $24.99
Mean: 17.49
Which statement is true given the data?

Answers

Answer:

C

Step-by-step explanation:

Anyone know the answer ?

Answers

Answer:

A.  SASD.  LL

Step-by-step explanation:

Two sides and the angle between are marked as congruent. That immediately tells you that the Side-Angle-Side (SAS) theorem of congruence applies.

The angle is a right angle, which makes the adjacent sides be "legs" of the right triangle. Then the Leg-Leg (LL) theorem of congruence for a right triangle also applies.

Appropriate choices are ...

  SAS, LL

The mean of the data set(9,5,y,2,x)is twice the data set (8,x, 4,1,3).What is (y-x)

Answers

Answer:

y - x = 16

Step-by-step explanation:

Explanation:-

Step(i):-

Given data set A  is  9,5,y,2,x

Mean of the Data set A

                         =   [tex]\frac{9 + 5 + y + 2 +x}{5}[/tex]

                         = [tex]\frac{16 +x+y}{5}[/tex]

Given data set B is 8, x, 4, 1, 3

Mean of the Data set B

                         =   [tex]\frac{8+ x+4+1+3}{5}[/tex]

Step(ii):-                          

Mean of the Data set A  = 2 X Mean of the Data set B

              [tex]\frac{16 +x+y}{5} = 2 X \frac{16+x}{5}[/tex]

On simplification , we get

           16 +x + y = 2( 16 +x)

           16 + x + y = 32 + 2 x

            16 + x + y - 32 - 2 x = 0

            y - x -16 =0

           y - x = 16

A triangle has sides of lengths 8, 15, and 17. Is it a right triangle? Explain.

Answers

Answer:

yes it does

17 is the longest side.

Iff  Iff 17%5E2+=+8%5E2+%2B+15%5E2 it's a right triangle.  it's a right triangle.

Ps "iff" means if and only if

hope it helps

if so please mark me  as brainliest

Consider the homogeneous second-order linear differential equation y′′+4y′−12y=0. Which of the following pairs gives two solutions to this equation? A. y1=e2x,y2=e−6x B. y1=e3x,y2=e1x C. y1=e2x,y2=e−2x D. y1=e−12x,y2=xe−12x E. y1=cos(−12x),y2=sin(−12x) F. y1=e−4x,y2=e−12x Then for these solutions find a particular solution of the form y=c1y1+c2y2 that satisfies the initial conditions y(0)=−5,y′(0)=0. y = y1 + y2.

Answers

Cc’ing chi c gg hi barb cub

Please answer this correctly

Answers

Answer:

452

Step-by-step explanation:

plz mark brainliest!

Answer:

i'll say you have to multiple 9 by 9 than 5 by 5 BUT 23 25 13 and 7 IDK sorry hope i helped :)

Step-by-step explanation:

A local coffee house surveyed 317 customers regarding their preference of chocolate chip or cranberry walnut scones . 150 customers prefer the Cranberry Walnut Scones . 81 customers who responded were males and prefer the Chocolate Chip Scones . 172 female customers responded . Find the probability that a customer chosen at random will be a male or prefer the Chocolate Chip Scones .

1. 25.6%
2. 24.1%
3. 72.9%
4. 98.4%

Answers

Answer:

3. 72.9%

Step-by-step explanation:

Let's call M the event that the customer is male and C the event that the customer prefer chocolate chips Scones.

So, the probability P(M∪C) that a customer chosen at random will be a male or prefer the Chocolate Chip Scones is calculated as:

P(M∪C) = P(M) + P(C) - P(M∩C)

Then, there are 145 males (317 customer - 172 females = 145 males), so the probability that the customer is a males is:

P(M) = 145/317 = 0.4574

There are 167 customers that prefer chocolate chips Scones ( 317 customers - 150 customers that prefer the Cranberry Walnut Scones = 167), so the probability that a customer prefer chocolate chips Scones is:

P(C) = 167/317 = 0.5268

Finally, 81 customers were males and prefer the Chocolate Chip Scones, so the probability that a customer will be a male and prefer chocolate  chip scones is:

P(M∩C) = 81/317 = 0.2555

Therefore,  P(M∪C) is equal to:

P(M∪C) = 0.4574 + 0.5268 - 0.2555

P(M∪C) = 0.7287

P(M∪C) = 72.9%

Answer:

3. 72.9%

Step-by-step explanation:

A probability is the number of desired outcomes divided by the number of total outcomes.

Desired outcomes:

Male or prefers the Chocolate Chip Scones. That is, males and females who prefer the Chocolate Chip Scones.

There are 172 female customers and 317-172 = 145 male customers.

150 customers prefer the Cranberry Walnut Scones. So 317 - 150 = 167 customers prefer the Chocolate Chip Scones.

81 of those are male, so 167 - 81 = 86 are female.

So the total of desired outcomes is 86 + 145 = 231

Total outcomes:

317 total customers.

Probability:

231/317 = 0.729

So the correct answer is:

3. 72.9%

A person needs to fill 20 water jugs with a hose. Filling the first 2 jugs has taken 3 minutes. How long to finish filling the remaining jugs

Answers

Answer:

Step-by-step explanation:

=20

This take 30 minutes to finish filling the remaining jugs.

What is Multiplication?

To multiply means to add a number to itself a particular number of times. Multiplication can be viewed as a process of repeated addition.

Given that;

A person needs to fill 20 water jugs with a hose. Filling the first 2 jugs has taken 3 minutes.

Now,

Let the time to finish filling the remaining jugs = x

Since, A person needs to fill 20 water jugs with a hose. Filling the first 2 jugs has taken 3 minutes.

Hence, By definition of proportion we get;

⇒ 20 / x = 2 / 3

⇒ 20 × 3 / 2 = x

⇒ x = 30

Thus, The time to finish filling the remaining jugs =  30 minutes

Learn more about the multiplication visit:

https://brainly.com/question/10873737

#SPJ2

Graph y < x2 + 4x. Click on the graph until the correct graph appears.

Answers

Answer:  The correct answer is:  

_________________________  

The given "graph" in the bottom right, lowest corner

Step-by-step explanation:

_________________________

Note:  When there is only one (1) equation give for a graph;

          and/or:  only one (1)  "inequality given";  

         we  look for the symbol.

If the symbol is "not" an "equals" symbol (i.e. not an:  =  symbol) ;

 we check for the type of "inequality" symbol.

If there is a:  "less than" (<) ;  or a "greater than" (>) symbol;  the graph of the "inequality" will have "dashed lines" (since there will be a "boundary").

If there is an "inequality" that is a: "less than or equal to" (≤) ;

                                                 or a: "greater than or equal to" (≥) ;

       →   then there will be not be a dashed line when graphed;

          but rather—a "solid line" ;  since "less than or equal to" ;

          or "greater than or equal to" —is similar to:

          "up to AND including"; or: "lesser/fewer than AND including".).

 _________________________  

Note:  We are given the "inequality" :

            →   " y <  x²  + 4x  "  .

_________________________________

Note that we have a "less than" symbol (< ) ; so the graph will have a:

   "solid line" [and not a "dotted line".].

_________________________________

Note that all of the graphs among our 4 answer choices have "dotted lines".

Not that all values (all x and y coordinated) within the "shaded portion" of the corresponding graph are considered part of the graph.  

As such, given any point within the shaded part,  the x and y coordinates must match the inequality (i.e. the given inequality must be true when one puts in the "x-coordinate" and "y-coordinate" into the "given inequality" :

→   " y <  x²  + 4x "  .

_________________________

Likewise, we can take any point within the "white, unshaded" portion of any of the graph, and take the "x-coordinate" and "y-coordinate" of that point, and the inequality: →   " y <  x²  + 4x  "  ;  will not hold true when the "x-coordinate" and "y-coordinate" values of that point— are substituted into the "inequality".  

_________________________

{Note:  Answer is continued on images attached.}.

Wishing you the best!

Suppose that a random sample of size 36 is to be selected from a population with mean 50 and standard deviation 7. What is the approximate probability that X will be within .5 of the population mean

Answers

Answer:

Step-by-step explanation:

Let us assume that x is normally distributed. The sample size is greater than 30. Since the the population mean and population standard deviation are known, we would apply the formula,

z = (x - µ)/(σ/√n)

Where

x = sample mean

µ = population mean

σ = standard deviation

n = number of samples

From the information given,

µ = 50

σ = 7

n = 36

If x is within 0.5 of the population mean, it means that x is between (50 - 0.5) and (50 + 0.5)

the probability is expressed as

P(49.5 ≤ x ≤ 50.5)

For x = 49.5

z = (49.5 - 50)/(7/√36) = - 0.43

Looking at the normal distribution table, the probability corresponding to the z score is 0.334

For x = 49.5

z = (50.5 - 50)/(7/√36) = 0.43

Looking at the normal distribution table, the probability corresponding to the z score is 0.666

Therefore,

P(49.5 ≤ x ≤ 50.5) = 0.666 - 0.334 = 0.332

The probability of drawing a pearl bead out of a bag of mixed beads is 2/3. What is the probability of drawing a bead which is not a pearl?

Answers

Answer:

[tex]\frac{1}{3}[/tex] probability of drawing a bead which is not a pearl

Step-by-step explanation:

For each bead that you draw, there are only two possible outcomes. Either it is a pearl bead, or it is not. The sum of these probabilities = 100% = 1.

So

2/3 probability of drawing a pearl bead.

p probability of drawing a non pearl bead.

What is the probability of drawing a bead which is not a pearl?

[tex]p + \frac{2}{3} = 1[/tex]

[tex]p = 1 - \frac{2}{3}[/tex]

[tex]p = \frac{3*1 - 2}{3}[/tex]

[tex]p = \frac{1}{3}[/tex]

[tex]\frac{1}{3}[/tex] probability of drawing a bead which is not a pearl

A farmer was interest in determining how many grasshoppers were in his field. He knows that the distribution of grasshoppers may not be normally distributed in his field due to growing conditions. As he drives his tractor down each row he counts how many grasshoppers he sees flying away. After several rows he figures the mean number of flights to be 57 with a standard deviation of 12. What is the probability of the farmer will count 52 or fewer flights on average in the next 40 rows down which he drives his tractor

Answers

Answer:

= 0.0041

Step-by-step explanation:

Given that:

A farmer was interest in determining how many grasshoppers were in his field. He knows that the distribution of grasshoppers may not be normally distributed in his field due to growing conditions. As he drives his tractor down each row he counts how many grasshoppers he sees flying away

mean number of flights to be 57

a standard deviation of 12

fewer flights on average in the next 40 rows

[tex]\mu = 57\\\\\sigma=12\\\\n=40[/tex]

so,

[tex]P(x<52)[/tex]

[tex]=P(\frac{x-\mu}{\sigma/\sqrt{n} } <\frac{52-57}{12/\sqrt{40} } )\\\\=P(z<\frac{-5\times6.325}{12} )\\\\=P(z<\frac{-31.625}{12})\\\\=P(z<-2.64)[/tex]

using z table

= 0.0041

The probability of the farmer will count 52 or fewer flights on average in the next 40 rows down which he drives his tractor is 0.0041 and this can be determined by using the properties of probability.

Given :

The distribution of grasshoppers may not be normally distributed in his field due to growing conditions.The mean number of flights to be 57 with a standard deviation of 12.

The probability of the farmer will count 52 or fewer flights on average in the next 40 rows down which he drives his tractor, can be determined by using the following calculations:

[tex]\rm P(x<52)=P\left (\dfrac{x-\mu}{\dfrac{\sigma}{\sqrt{n} }}<\dfrac{52-57}{\dfrac{12}{\sqrt{40} }}\right)[/tex]

[tex]\rm P(x<52)=P\left (z<\dfrac{-5\times 6.325}{12 }}\right)[/tex]

[tex]\rm P(x<52)=P\left (z<\dfrac{-31.625}{12 }}\right)[/tex]

[tex]\rm P(x<52)=P\left (z<-2.64\right)[/tex]

Now, using z-table:

P(x < 52) = 0.0041

For more information, refer to the link given below:

https://brainly.com/question/21586810

A city has just added 100 new female recruits to its police force. The city will provide a pension to each new hire who remains with the force until retirement. In addition, if the new hire is married at the time of her retirement, a second pension will be provided for her husband. A consulting actuary makes the following assumptions: (i) Each new recruit has a 0.4 probability of remaining with the police force until retirement. (ii) Given that a new recruit reaches retirement with the police force, the probability that she is not married at the time of retirement is 0.25. (iii) The events of different new hires reaching retirement and the events of different new hires being married at retirement are all mutually independent events. Calculate the probability that the city will provide at most 90 pensions to the 100 new hires and their husbands. (A) 0.60 (B) 0.67 (C) 0.75 (D) 0.93 (E) 0.99

Answers

Answer:

E) 0.99

Step-by-step explanation:

100 recruits x 0.4 chance of retiring as police officer = 40 officers

probability of being married at time of retirement = (1 - 0.25) x 40 = 30 officers

each new recruit will result in either 0, 1 or 2 new pensions

0 pensions when the recruit leaves the police force (0.6 prob.)1 pension when the recruit stays until retirement but doesn't marry (0.1 prob.)2 pensions when the recruit stays until retirement and marries (0.3 prob.)

mean = µ = E(Xi) = (0 x 0.6) + (1 x 0.1) + (2 x 0.3) = 0.7

σ²  = (0² x 0.6) + (1² x 0.1) + (2² x 0.3) - µ² = 0 + 0.1 + 1.2 - 0.49 = 0.81

in order for the total number of pensions (X) that the city has to provide:

the normal distribution of the pension funds = 100 new recruits x 0.7 = 70 pension funds

the standard deviation = σ = √100 x √σ² = √100 x √0.81 = 10 x 0.9 = 9

P(X ≤ 90) = P [(X - 70)/9] ≤ [(90 - 70)/9] =  P [(X - 70)/9] ≤ 2.22

z value for 2.22 = 0.9868 ≈ 0.99

One side of a rectangle is 14 meters. The perimeter of the rectangle is 44 meters. What is the area of this rectangle?

Answers

The area of the rectangle is 112 meters

How would you use a completely randomized experiment in each of the following settings?
Is a placebo being used or not? Be specific and give details.

a. A charitable nonprofit organization wants to test two methods of fund-raising. From a list of 1000 past donors, half will be sent literature about the successful activities of the charity and asked to make another donation. The other 500 donors will be contacted by phone and asked to make another donation. The percentage of people from each group who make a new donation will be compared.

b. A tooth-whitening gel is to be tested for effectiveness. A group of 85 adults have volunteered to participate in the study. Of these. 43 are to be given a gel that contains the tooth-whitening chemicals. The remaining 42 are to be given a similar-looking package of gel that does not contain the tooth-whitening chemicals. A standard method will be used to evaluate the whiteness of teeth for all participants. Then the results for the two groups will be compared. How could this experiment he designed to be double-blind?

c. Consider the experiment described in part (a). Describe how you would use a randomized block experiment with blocks based on age. Use three blocks: donors younger than 30 years old. donors 30 to 59 years old. donors 60 and older.

Answers

Answer:

Step-by-step explanation:

a. Two methods of fund raising is being tested here in the first case study. To make a completely randomized experiment. I would use and randomly assign half the population of the 1000 donor sample that will be sent literature about the successful activities of the charity and asked to make another donation to one of the two treatment conditions: which is a sent literature about the successful activities of the charity. While the placebo group would be the other 500 donors contacted by phone and asked to make another donation with no influence whatever from the charity.

b. For the second case study, To make a completely randomized experiment. I would use and randomly assign 43 particupants which are to be given a gel that contains the tooth-whitening chemicals to the treatment condition containing the tooth-whitening chemicals while the placebo group would be the remaining 42 which are to be given a similar-looking package of gel that does not contain the tooth-whitening chemicals.

c. Using three blocks: the completely randomized design experiment would be:

Donors younger than 30 years old:

Sent literature: Yes No

Contact by phone: Yes No

Donors 30 to 59 years old:

Sent literature: Yes No

Contact by phone: Yes No

Donors 60 and older:

Sent literature: Yes No

Contact by phone: Yes No

(Yes means yes to another donation and No means no to another donation)

Answer:

Step-by-step explanation:

a. Two methods of fund raising is being tested here in the first case study. To make a completely randomized experiment. I would use and randomly assign half the population of the 1000 donor sample that will be sent literature about the successful activities of the charity and asked to make another donation to one of the two treatment conditions: which is a sent literature about the successful activities of the charity. While the placebo group would be the other 500 donors contacted by phone and asked to make another donation with no influence whatever from the charity.

b. For the second case study, To make a completely randomized experiment. I would use and randomly assign 43 particupants which are to be given a gel that contains the tooth-whitening chemicals to the treatment condition containing the tooth-whitening chemicals while the placebo group would be the remaining 42 which are to be given a similar-looking package of gel that does not contain the tooth-whitening chemicals.

c. Using three blocks: the completely randomized design experiment would be:

Donors younger than 30 years old:

Sent literature: Yes No

Contact by phone: Yes No

Donors 30 to 59 years old:

Sent literature: Yes No

Contact by phone: Yes No

Donors 60 and older:

Sent literature: Yes No

Contact by phone: Yes No

(Yes means yes to another donation and No means no to another donation)

Please answer this correctly

Answers

Answer:

676

Step-by-step explanation:

lxw

14x35

4x24

6x15

676

∠BAD is bisected by . If m∠BAC = 2x - 5 and m∠CAD = 145, the value of x is:

Answers

Answer:

x = 75

Step-by-step explanation:

Assuming the angles are equal  ( bisected means divided in half)

2x-5 = 145

Add 5 to each side

2x-5+5 = 145+5

2x = 150

Divide by 2

2x/150/2

x = 75

Answer:

x=75

Step-by-step explanation:

∠BAD is bisected by AC and measurement of BAC is equal to 2x - 5 and measurement of CAD is equal to 145. Since they are bisected, they are equal and the solution is shown below:

m ∠ BAC = m ∠ CAD

2x - 5 = 145 , transpose -5 to the opposite side such as:

2x = 145 + 5 , perform addition of 145 and 5

2x = 150

2x / 2 = 150 / 2 , divide both sides by 2

x = 75

The answer is 75 for the x value.

Graph the line with slope -1/3 and y -intercept 6 .

Answers

Answer:

plot a point at 6 up from (0,0) and then go down one and over three places then plot another point- and so on - and so on

Step-by-step explanation:

To graph the line using the slope and intercept, first understand what the slope and intercept mean:

Slope is how steep or flat the line appears on the graph.

A very high or low slope (100 or -100) will be very steep on the graph.A slope very close to zero (0.0001 or -0.0001) will be very flat on the graph.A positive slope will travel northeast and southwest (for linear equations).A negative slope will travel northwest and southeast (for linear equations).

The y-intercept is the point at which the line hits the y-axis. In this equation, the line hits the y-axis at positive 6, which means that the point is (0, 6).

You can use a method called "rise over run" to graph. The slope is negative one over three, so the line will "rise" negative one units after "running" three units.

So, for every one unit down, the line will travel three units to the right.

Graph this from the point (0, 6), your y-intercept, and plot the points according to the slope:

Find the produce 2 1/3 times 3 1/2

Answers

Answer:

49/6 or 8 16/99

Step-by-step explanation:

2 1/3 *3 1/2 = (7/3*7/2)= 49/6

First convert to fraction form

then multiply across numerator to numerator and denominator to deominator

Simplify if needed

Turn to mixed fraction if needed

Which expession is equivalent to -3(6c + 2) + 5c

Answers

Answer:

-13c-6

Step-by-step explanation:

-3(6c + 2) + 5c

Distribute

-18c -6 +5c

Combine like terms

-13c-6

Answer:

-13c -6

Step-by-step explanation:

-3 (6c) -3x2+5c

multiply 6 by -3

-18c-3x2+5c

multiply -3 by 2

-18c -6+ 5c

add 18c and 5c

-13c -6

if F (x) equals 4x + 7 which of the following is the inverse of F(x)​

Answers

Answer:

  [tex]F^{-1}(x)=\dfrac{x-7}{4}[/tex]

Step-by-step explanation:

To find the inverse function, solve for y the relation ...

  F(y) = x

  4y +7 = x

  4y = x - 7

  y = (x -7)/4 . . . . the inverse function

  [tex]\boxed{F^{-1}(x)=\dfrac{x-7}{4}}[/tex]

Answer: B

4x+7=y

Subtract 7 from both sides

4x=y-7

Divide both sides by 4

x= (y-7)/4

Switch x and y

y= (x-7)/4

So the answer is B

Classify the triangle by its​ sides, and then by its angles.
128 degrees
26 degrees
26 degrees
16 cm
16 cm
28 cm
Classified by its​ sides, the triangle is​ a(n)

isosceles
scalene
equilateral
triangle.
Classified by its​ angles, the triangle is​ a(n)

obtuse
acute
right
triangle.

Answers

The two equal sides make it an ISOSCELES triangle, the 128* angle makes it an OBTUSE triangle

What’s the correct answer for this question?

Answers

Answer:

A and B

Step-by-step explanation:

1) Distance to the focus

From (x,y) to the focus(2,-4) {using distance formula}

=√(x-2)²+(y+4)²

2) Distance to the directrix

Is, y+p where P here is (-6)

So

d2 = y+p

= y+(-6)

= y-6

COMPUTE:
A) 40−5÷ 1/5 =
B) (4.8−1.8÷6)÷5=

Answers

Answer:

A) 15

B) 0.9

Step-by-step explanation:

Use the correct order of operations.

A) 40 − 5 ÷ 1/5 =

= 40 − 5 * 5

= 40 - 25

= 15

B) (4.8 − 1.8 ÷ 6) ÷ 5 =

= (4.8 − 0.3) ÷ 5

= 4.5 ÷ 5

= 0.9

A tank contains 5,000 L of brine with 13 kg of dissolved salt. Pure water enters the tank at a rate of 50 L/min. The solution is kept thoroughly mixed and drains from the tank at the same rate.

Required:
a. How much salt is in the tank after t minutes?
b. How much salt is in the tank after 20 minutes?

Answers

Answer:

a) [tex]x(t) = 13*e^(^-^\frac{t}{100}^)[/tex]

b) 10.643 kg

Step-by-step explanation:

Solution:-

- We will first denote the amount of salt in the solution as x ( t ) at any time t.

- We are given that the Pure water enters the tank ( contains zero salt ).

- The volumetric rate of flow in and out of tank is V(flow) = 50 L / min  

- The rate of change of salt in the tank at time ( t ) can be expressed as a ODE considering the ( inflow ) and ( outflow ) of salt from the tank.

- The ODE is mathematically expressed as:

                            [tex]\frac{dx}{dt} =[/tex] ( salt flow in ) - ( salt flow out )

- Since the fresh water ( with zero salt ) flows in then ( salt flow in ) = 0

- The concentration of salt within the tank changes with time ( t ). The amount of salt in the tank at time ( t ) is denoted by x ( t ).

- The volume of water in the tank remains constant ( steady state conditions ). I.e 10 L volume leaves and 10 L is added at every second; hence, the total volume of solution in tank remains 5,000 L.

- So any time ( t ) the concentration of salt in the 5,000 L is:

                             [tex]conc = \frac{x(t)}{1000}\frac{kg}{L}[/tex]

- The amount of salt leaving the tank per unit time can be determined from:

                         salt flow-out = conc * V( flow-out )  

                         salt flow-out = [tex]\frac{x(t)}{5000}\frac{kg}{L}*\frac{50 L}{min}\\[/tex]

                         salt flow-out = [tex]\frac{x(t)}{100}\frac{kg}{min}[/tex]

- The ODE becomes:

                               [tex]\frac{dx}{dt} = 0 - \frac{x}{100}[/tex]

- Separate the variables and integrate both sides:

                       [tex]\int {\frac{1}{x} } \, dx = -\int\limits^t_0 {\frac{1}{100} } \, dt + c\\\\Ln( x ) = -\frac{t}{100} + c\\\\x = C*e^(^-^\frac{t}{100}^)[/tex]

- We were given the initial conditions for the amount of salt in tank at time t = 0 as x ( 0 ) = 13 kg. Use the initial conditions to evaluate the constant of integration:

                              [tex]13 = C*e^0 = C[/tex]

- The solution to the ODE becomes:

                           [tex]x(t) = 13*e^(^-^\frac{t}{100}^)[/tex]

- We will use the derived solution of the ODE to determine the amount amount of salt in the tank after t = 20 mins:

                           [tex]x(20) = 13*e^(^-^\frac{20}{100}^)\\\\x(20) = 13*e^(^-^\frac{1}{5}^)\\\\x(20) = 10.643 kg[/tex]

- The amount of salt left in the tank after t = 20 mins is x = 10.643 kg

                           

Please hurry
On each bounce, a ball dropped from 100 feet rises to the height
from which it has fallen. How high does the ball rise, in feet, on the 10th bounce?

Answers

Answer:

D

Step-by-step explanation:

divide 10 times starting with 100.

The answer is 25/256 or 0.09765625

The height of the ball dropped from 100 feet on the 10th bounce is 0.09766 feet

What is an equation?

An equation is an expression that shows the relationship between two or more numbers and variables.

Let y represent the height of the ball after x bounce. Given that the ball rises to the height from which it has fallen, hence:

y = 100(1/2)ˣ

After the 10th bounce:

y = 100(1/2)¹⁰ = 0.09766

The height of the ball dropped from 100 feet on the 10th bounce is 0.09766 feet.

Find out more on equation at: https://brainly.com/question/2972832

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