The first term in the sequence 5, 7, −7, ... is 5. Each even-numbered term is 2 more than the previous term and each odd-numbered term, after the first, is (−1) times the previous term. For example, the second term is 5+2 and the third term is (−1)×7. What is the 255th term of the sequence?

Answer:

SD = 5.987, Var(X) = 35.85

Step-by-step explanation:

Apply the standard deviation formula, remembering that n represents the sample size. Then, just take the square of the standard deviation to obtain the variance.

Hope this helps!

Answer:

175

Step-by-step explanation:

+ × - = -

thus 199+(-24)

199-24

175

Answer: 199 + -24 = 175

Step-by-step explanation: 199 is a positive number and -24 is a negative number. If the positive number is bigger than the negative number you subtract. So forget that the - sign is there and subtract it.  

Answer:

[tex]x=15^\circ[/tex]

Step-by-step explanation:

Please refer to the attached figure for labeling of given diagram:

We are given the following angles:

[tex]\angle AOC = 3x^\circ\\\angle BOD = 2x^\circ\\\angle EOF = 7x^\circ[/tex]

Angles opposite to each other when they are formed by crossing of two lines are known as vertically opposite angles. And vertically opposite angles are always equal to each other.

Using property of vertically opposite angles:

[tex]\angle EOF = \angle AOB = 7x^\circ[/tex]

Line CD is a straight line, so [tex]\angle COD = 180^\circ[/tex]

Also,

[tex]\angle COD = \angle COA+\angle AOB+\angle BOD = 180^\circ\\\Rightarrow 3x + 7x + 2x=180^\circ\\\Rightarrow 12x =180^\circ\\\Rightarrow x = \dfrac{180}{12}\\\Rightarrow x = 15^\circ[/tex]

Hence, answer is [tex]x = 15^\circ[/tex].

Answer:

(a) Roughly 68% of vehicle speeds were between 27 and 57 mph.

(b) Roughly 16% of vehicle speeds exceeded 57 mph.

Step-by-step explanation:

We are given that in a study investigating the effect of car speed on accident severity, 5000 reports of fatal automobile accidents were examined.

For these 5000 accidents, the average speed was 42 mph and the standard deviation was 15 mph.

Let X = vehicle speed at impact

SO, X ~ Normal([tex](\mu=42,\sigma^{2} = 15^{2}[/tex])

Here, [tex]\mu[/tex] = population average speed = 42 mph

         [tex]\sigma[/tex] = standard deviation = 15 mph

Since, the distribution is approximately normal; so the 68-95-99.7 empirical rule states that;

(a) Since, it is stated above that 68% of the data values lies within one standard deviation points, that means;

68% data values will lie between [ [tex]\mu-\sigma , \mu+\sigma[/tex] ] , i.e;

        [ [tex]\mu-\sigma , \mu+\sigma[/tex] ]  =  [42 + 15 , 42 - 15]

                                 =  [57 , 27]

So, it means that roughly 68% of vehicle speeds were between 27 and 57 mph.

(b) We have observed above that roughly 68% of vehicle speeds were between 27 and 57 mph which leads us to the conclusion that (100% - 68% = 32%) of the data values will be outside this range.

It is stated that of this 32%, half of the data values will be less than 27 mph and half of the data values will be more than 57 mph.

This means that roughly 16% of vehicle speeds exceeded 57 mph.

Answer:

Option D

Step-by-step explanation:

This question is based on the " Partition Postulate. " You might be familiar with it, it states that a whole is composed of several parts. In this case you could say that this " whole " is ∠ ABC, and the " parts " are ∠1 and ∠2. By this Theorem you could also state the following;

[tex]m< ABC = m< 1 + m< 2,\\\\Substitute,\\110 = 4x + ( 5x + 10 ),\\110 = 4x + 5x + 10,\\4x + 5x + 10 = 110 - Option D\\\\Solution - Option D[/tex]

Hope that helps!

Answer:

46/ 67

Step-by-step explanation:

The numbers of students irrespective of grades is;

The sum of the last roll of numbers:

10+24+ 33+ 67 = 134

The number of males irrespective of grades is the sum of the numbers in the male row ;

7 +20+ 14 +41= 82

The numbers of students with grade A is the first column at the last row and is 10;

Hence;

the probability that the student was male OR got an 'A' is

the probability that the student was male plus the probability that he/she got an 'A'.

The probability that it's a male is ;

Number of males/ total number of students

=82/134

The probability that he got an A is;

The number of students that got A/ the total number of students;

10/134

Hence

the probability that the student was male OR got an 'A' is;

82/ 134 + 10/134 = 92/134 = 46/ 67

Answer:

x = 1/9

Step-by-step explanation:

3^ (x+1) = 9 ^ (5x)

Replace 9 with 3^2

3^ (x+1) = 3^2 ^ (5x)

We know that a^b^c = a ^(b*c)

3^ (x+1) = 3^(2 * (5x))

3^ (x+1) = 3^(10x)

The bases are the same so the exponents are the same

x+1 = 10x

Subtract x from each side

x+1-x = 10x-x

1 = 9x

Divide each side by 9

1/9 = 9x/9

1/9 =x

Answer:

Brainelist?

Step-by-step explanation:

7-4i

just use a online calculator

Answer:

7-4i

Step-by-step explanation:

(2 - 3i)(2 + i)​

FOIL

first 2*2 = 4

Outer: 2i

Inner: -3i*2 = -6i

Last: -3i*i = -3i^2 = -3(-1) = 3

Add them together

4+2i-6i+3

7-4i

Answer:

Step-by-step explanation:

Let x be a random variable representing the number of guesses made for the sat questions.

Since the probability of getting the correct answer to a question is fixed for any number of trials and the outcome is either getting it correctly or not, then it is a binomial distribution. The probability of success, p = 0.2

Probability of failure, q = 1 - p = 1 - 0.2 = 0.8

the probability that the number x of correct answers is fewer than 4 is expressed as

P(x < 4)

From the binomial distribution calculator,

P(x < 4) = 0.97

Answer:

If we have a cone-shape candle with r=2 cm and h=3 cm, then the amount of paper needed is 18.84 cm^2 and the amount of plastic needed is 12.56 cm^2.

Step-by-step explanation:

The question is incomplete: no numerical values for the dimensions of the cone are given.

A right cone is defined by the radius r of the base and the height h.

The base area is the area of a circle with radius r:

[tex]A_b=\pi r^2[/tex]

The lateral area is calculated as:

[tex]A_l=\pi \cdot r\cdot l[/tex]

As the values for r and h are not given, we will use an example with r=2 and h=3.

Then, the amount of paper needed is:

[tex]A_l=\pi \cdot r\cdot l=3.14\cdot (2\,cm)\cdot (3\, cm)=18.84\,cm^2[/tex]

The amount of plastic needed is:

[tex]A_b=\pi r^2=3.14\cdot (2\,cm)^2=3.14\cdot 4\,cm^2=12.56\,cm^2[/tex]

Answer:

a= -3/8

b= 1/8

Step-by-step explanation:

To remove i from the denominator, we need to multiply the numerator and denominator by -i

[tex]\frac{(-1-3i)(-i)}{8i(-i)}[/tex]

This simplifies to

[tex]\frac{i+3i^{2} }{-8i^{2} }[/tex]

This further simplifies to

[tex]\frac{i-3}{8}[/tex]

This can be rewritten as

[tex]-\frac{3}{8} +\frac{1}{8} i[/tex]

a= -3/8

b= 1/8

Answer:

[tex] a = - \frac{3}{8} \\ \\ b = \frac{1}{8} [/tex]

Step-by-step explanation:

[tex] \frac{ - 1 - 3i}{8i} \\ \\ = \frac{ - 1 - 3i}{8i} \times \frac{i}{i} \\ \\ = \frac{( - 1 - 3i)i}{8i \times i} \\ \\ = \frac{ -1 \times i - 3 {i}^{2} }{8 {i}^{2} } \\ \\ = \frac{ - i - 3 ( - 1)}{8 ( - 1) } \\ \\ = \frac{ - i + 3}{ - 8} \\ \\ = \frac{ i - 3}{ 8} \\ \\ = \frac{ - 3 + i}{ 8} \\ \\ = \frac{ - 3}{8} + \frac{i}{8} \\ \\ \purple{ \bold{ = - \frac{3}{8} + \frac{1}{8} i}} \\ equating \: it \: with \: a + bi \\ \\ a = - \frac{3}{8} \\ \\ b = \frac{1}{8} \\ [/tex]

Answer:

[tex]\frac{8}{49}[/tex]

Step-by-step explanation:

Orange: [tex]\frac{4}{7}[/tex]

Red: [tex]\frac{2}{7}[/tex]

[tex]\frac{4}{7} *\frac{2}{7} =\frac{8}{49}[/tex]

Answer:

52300

Step-by-step explanation:

When you multiply by ten the decimal dot moves one space to the right, so here you multiply by ten four times, so you move the dot four spaces to the right and you get 52300

Answer:

Step-by-step explanation:

a)4a-6a                   d)2x+4y-10x

   =-2a.                     =-8-+4y

b)14-1-10

=3

c)2+8

=10

e)answer is 6 x raised to the power 3

f)7x raised to the power 2-5x-y

Answer:

The answer is y = -3x - 2.

Step-by-step explanation:

Given that in slope-form equation, m represents gradient and c is y-intercept. So you have to sbustitute the values into the equation :

[tex]y = mx + c[/tex]

[tex]let \: m = - 3 \\ let \: c = - 2[/tex]

[tex]y = - 3x - 2[/tex]

Answer:

The mass of the grains = 120 ± 1 g

Step-by-step explanation:

we are given the following:

Total mass of container + grains = 185 grams

Mass of container = 65 grams

Therefore, mass of grains is calculated as follows:

Mass of grains = ( Mass of container + grains) - mass of container

= 185 - 65 = 120 grams.

since the scale has an absolute uncertainty of 1 g, the mass of the grains is written as 120 ± 1 g

Answer:

b. external validity

Step-by-step explanation:

External Validity is the applicability of the results of an experiment to the real world. Most times, there are threats to the validity of an experiment which could result in little or no effect on the general population. For example, if the method of selection reflects a measure of bias, then this could affect the result. Also if the participants are taking different aspects of the same test, it could also affect its validity as they may not be able to make a correct conclusion. If the sample size is not reflective of the entire population, it could also pose a threat to the validity of the experiment.

John's experiment is weak in its external validity because it cannot be generalized to the entire population of customers. He has to identify the threats to the validity of his experiment and correct them. For example, the sample selection may be biased.

Answer:

x <= 48

Step-by-step explanation:

Subtract 3 from both sides

x/12 <= 4

Multiply by 12

x <= 48

Answer:

The rooms should be rented at $75 per day for a maximum income of $11250 per day.

Step-by-step explanation:

If the daily rental is increased by $ x

then

Rental:  R (x )=( 40 + x )  dollars per room-day

Number of rooms rented:  N ( x ) = ( 220 − 2 x )  and

Income:  I ( x ) = ( 40 + x ) ( 220 − 2 x ) =8800+140x-2x²  dollars/day

The maximum will be achieved when the derivative of  I ( x )  is zero.

[tex]\frac{dI(x)}{dx} =140-4x=0[/tex]

x=35

so, ($40+$35)=75$per day

 I ( x35) =8800+140(35)-2(35)²= 11250

The answer is 1 7/20

2/5 x 4/4 + 7/10 x 2/2 + 1/4 x 5/5

=  8/20 + 14/20 + 5/20

= 27/20

= 1 7/20

Answer:

27/20 or 1 and 7/20

Step-by-step explanation:

All you do is find common factors.

The factorisation of the given equation using completing square method is (x+12)²=177. Therefore, option D is correct.

The given equation is x²+24x=33.

We need to factorise the equation using completing the square method.

Completing the square means writing a quadratic in the form of a squared bracket and adding a constant if necessary.

Now, x²+24x-33=0

Add and subtract (b/2)²=144 to the equation.

x²+24x-33+144-144=0

⇒x²+24x+144-33-144=0

⇒(x+12)²-177=0

⇒(x+12)²=177

The factorisation of the given equation using completing square method is (x+12)²=177. Therefore, option D is correct.

To learn more about completing the square method visit:

https://brainly.com/question/26107616.

#SPJ2

Answer:

For ease of writing, θ [tex]=x[/tex]

[tex]sin(x)=\frac{1}{\sqrt{2} }[/tex]

[tex]cos(x)=-\frac{1}{\sqrt{2} }[/tex]

Step-by-step explanation:

Our angle is [tex]x=\frac{3\pi }{4}[/tex]

To find our answers for [tex]sin(\frac{3\pi}{4} )[/tex] and [tex]cos(\frac{3\pi}{4} )[/tex], we will need to use a unit circle. (I have attached the image of one).

Recall that the [tex]sin[/tex] of an angle is equal to the y-value of the corresponding ordered pair.

And the [tex]cos[/tex] of an angle is equal to the x-value of the corresponding ordered pair.

For the angle [tex]x=\frac{3\pi }{4}[/tex], the ordered pair is [tex](-\frac{1}{\sqrt{2}} }, \frac{1}{\sqrt{2} } )[/tex]

This means that

[tex]sin(x)=\frac{1}{\sqrt{2} }[/tex]

[tex]cos(x)=-\frac{1}{\sqrt{2} }[/tex]

Answer:

= ( $72.756, $110.804)

Therefore, the 90% confidence interval (a,b) = ( $72.756, $110.804)

Critical value at 90% confidence = 1.645

Step-by-step explanation:

Confidence interval can be defined as a range of values so defined that there is a specified probability that the value of a parameter lies within it.

The confidence interval of a statistical data can be written as.

x+/-zr/√n

Given that;

Mean x = $91.78

Standard deviation r = $23.13

Number of samples n = 4

Confidence interval = 90%

Using the z table;

z(α=0.05) = 1.645

Critical value at 90% confidence = 1.645

Substituting the values we have;

$91.78+/-1.645($23.13/√4)

$91.78+/-1.645($11.565)

$91.78+/-$19.024425

$91.78+/-$19.024

= ( $72.756, $110.804)

Therefore, the 90% confidence interval (a,b) = ( $72.756, $110.804)

Answer:

1.5 meters

Step-by-step explanation:

The formula for the area of a trapezoid is h * (a+b)/2, where a is the first base and b is the second base. Now, we can work backwards to determine the height of the trapezoid:

3.75=h*(1.7+3.3)/2

3.75=h*2.5

h=3.75/2.5=1.5

Hope this helps!

Answer:

Step-by-step explanation:

use the formula and rearrange for h.

1/2 x h x  (a + b) = A

1/2 x (1.7 + 3.3) x h = 3.75

2.5 x h = 3.75

h = 1.5

hope this helps! :)

Answer:82

Step-by-step explanation:

a+b+c+d+e+f/6=72

a+b+c+d+e+f=6*72

a+b+c+d+e+f=432

a+b+c+d+e+f+g+h/8=74.25

a+b+c+d+e+f+g+h=594

g=80

h=?

432+80+h=594

512+h=594

h=82

hope it helps brainleast plz...

Answer:

10,15.20.25

Step-by-step explanation:

+5 in each number

Answer:

B.

Step-by-step explanation:

Since two diameters are intersecting eachother, the angles inside them would be vertical angles so they'll be congruent.

So

m<LYM = m<JYM

Also their arcs would be equal to their angles measures so,

Arc JK = 52°

Answer:

n = 3 or n = 4

Step-by-step explanation:

Let the unknown number be n.  

Then:

n² = 7n - 12

In standard quadratic form, we have:

n² - 7n + 12 = 0

In factored form, we have:

(n - 3)(n - 4) = 0, and so

n = 3 and n = 4

Answer:

Donde didn't multiply 4(1+3i)

Answer: it’s A he did not apply distributive property yo

Step-by-step explanation: