Un padre para estimular a su hijo para estudiar matemáticas le dice: por cada ejercicio que resuelvas bien te daré 7 € y por cada uno que hagas mal me darás 1 €. Después de hacer 45 ejercicios, el muchacho se encuentra con 19 €. ¿Cuántos ejercicios ha resuelto bien?

Answers

Answer 1

Answer:

8 ejercicios

Step-by-step explanation:

De acuerdo a la información dada, puedes plantear las siguientes ecuaciones:

x+y= 45 (1)

7x-1y= 19 (2)

x= ejercicios que resolvió bien

y= ejercicios que resolvió mal

Primero, puedes despejar x en (1):

x= 45-y (3)

Segundo, debes reemplazar (3) en (2):

7(45-y)-1y=19

315-7y-1y= 19

315-8y= 19

315-19= 8y

296= 8y

y= 296/8

y= 37

Tercero, debes reemplazar el valor de y en (3) para encontrar x:

x= 45-37

x= 8

De acuerdo a esto, la respuesta es que el hijo ha resuelto bien 8 ejercicios.


Related Questions

Can someone help me with this question ? 10points.

Answers

It is the one on the farthest right

part 2. Find the measure of the indicated angle to the nearest degree​

Answers

Answer:

i hope this helps you

Find the angle A if angle B is 60 degrees and angle A and angle B are complementary

Answers

Answer:

30 degrees

Step-by-step explanation:

Complimentary = 90 degrees

90 - 60 = 30 degrees

A number is increased by 2 and then multiplied by 3. The result is 24. What is this number

Answers

Answer:

The answer is 6.

Step-by-step explanation:

To find this answer, divide 24 by 3 and you get 8. 8 minus 2 is 6.

If f(x) = 3x-2 and g(x) = 2x + 1 find (f-g)(x)

Answers

Answer:

x-3

Step-by-step explanation:

f(x) = 3x-2

g(x) = 2x + 1

(f-g)(x) = 3x-2 - (2x+1)

Distribute the minus sign

          =3x-2-2x-1

Combine like terms

        = 3x-2x-2-1

        =x-3

Find the midpoint between the two points of the line in the image below.

Answers

Answer:

(-2,0.5)

Step-by-step explanation:

1st set of Point=(-5,-2)

2nd set  of Point=(1,3)

Midpoint=(X1+X2/2 , Y1+Y2/2)

=(-5+1/2 , -2+3/2)

=(-2,0.5)

Please someone help me

Answers

Answer:

y=7*3^x

Step-by-step explanation:

y=ab^x

(0,7) ⇒ 7=ab^0 ⇒ 7=a

(5, 1701) ⇒ 1701= 7b^5 ⇒ b^5=243 ⇒ b^5= 3^5 ⇒ b=3

y=7*3^x

state what additional information is required in order to know that the triangles are congruent by SSS​

Answers

Answer:  d) DF ≅ JH

Step-by-step explanation:

Side-Side-Side Congruency Theorem states that triangles are congruent if and only if their corresponding side lengths are congruent.

Given: EF ≅HI

Given: DE ≅IJ

Missing: DF ≅ JH

a Fair coin is tossed 3 times. What is the probability of getting at least one heads and at least one tails?​

Answers

Answer:

b. 75%

Step-by-step explanation:

Here are all the outcomes of three coin tosses:

HHH

HHT

HTH

HTT

THH

THT

TTH

TTT

There are a total of 8 possible outcomes.

1 outcome is all heads.

1 outcome is all tails.

6 outcomes have at least one heads and 1 tails

p(at least 1 heads and at least 1 tails) = 6/8 = 3/4 = 75%

Find the volume of a cone. Either enter an exact answer in terms of or use 3.14 for pi and round your final answer to the nearest hundredth. The radius is 2 the height is 9

Answers

Answer:

12 units³

Step-by-step explanation:

The required formula is V = (1/3)πr²h, where r is the radius and h is the height.  Here we get:

V = (1/3)π(2)²(9) = (1/3)π(9)(4) = 12 units³

What is the slope of the line shown?

Answers

Answer:

1/2

Step-by-step explanation:

The slope is one half, because every time x increases by 1, y increases by 1/2. You can find the slope using the rise over run strategy. You choose a point, and you also choose the point to the right of the point you first chose. You then count how many units up and to the right the right point is.

Its Up/Right.

This version of rise over run however only works when the line is going up.

LMN is a right triangle. True or False

Answers

Answer:

False

Step-by-step explanation:

Let us check using Pythagorean Theorem

[tex]c^2 = a^2 + b^2[/tex]

Where c is the hypotenuse (14), a is the base (13) and b is the perpendicular (5)

Putting in the above formula

[tex]14^2 = 13^2 + 5^2[/tex]

196 = 169+25

196 ≠ 194

So, It is not a right angled triangle

Anyone mind helping out with my math?

Answers

Answer:

no

Step-by-step explanation:

all the numbers are multiples of each two.

For example,

2×2=4,

4×2=8,

8×2=16

So, the line would be linear.

// have a great day //

A vegetable garden measures 20m x 30m. He wants to double the area by adding a strip of ground around the outside. How wide should the strip be?

Answers

Answer:

Step-by-step explanation:

what is the value of y in the equation 6.4x + 2.8y = 44.4, when x = 3?

Answers

Answer

y=45

Step-by-step explanation:

Answer:

9

Step-by-step explanation:

6.4 × 3 =19.2

44.4 - 19.2 =2.8y

25.2=2.8y

25.2/2.8=y

y=9

Dos motos, A y B, toman la salida en una carrera de 90 km. La moto A realiza el recorrido con una velocidad media inferior en 20 km/h a la de la moto B, con lo que llega a la meta 3 minutos después que B. Calcula la velocidad de cada moto.

Answers

Answer:

motorcycle A: 180 km/h

motorcycle B: 200 km/h

Step-by-step explanation:

To solve this question we need to write a system of equations for A and B, using the equation:

distance = speed * time

The speed of A is 20 less than the speed of B, so:

speedA = speedB - 20

And the time A traveled is 3 minutes (0.05 hours) more than B's time, so:

timeA = timeB + 0.05

Then, using the distance equation, we have that:

distanceB = speedB * timeB

90 = speedB * timeB

distanceA = speedA * timeA

90 = (speedB - 20) * (timeB + 0.05)

90 = speedB * timeB + 0.05 * speedB - 20*timeB - 1

90 = 90 + 0.05 * speedB - 20*timeB - 1

20*timeB = 0.05 * speedB - 1

timeB = (speedB - 20)/400

using this timeB in the distance equation, we have:

90 = speedB * (speedB - 20)/400

90 * 400 = speedB^2 - 20*speedB

speedB^2 - 20*speedB - 36000 = 0

Solving this quadratic equation, we have speedB = 200 km/h

And the speedA is:

speedA = speedB - 20 = 200 - 20 = 180 km/h

What is the answer please help 3(2+8)

Answers

Answer:

30

Step-by-step explanation:

3*10 = 30

Answer:

30

Step-by-step explanation:

PEMDAS says you do (8+2) first, which equals 10, then you multiply 3 by 10, which equals 30.

Two numbers add to 200. The first is 20 less than the second. What are the numbers?

Answers

Answer:

Step-by-step explanation:

Let's call the first number x.

We can write an equation representing the problem using x:

x+x+20=200 (because the second number is 20 more than the first, or x)

Combine like terms: 2x+20=200

Subtract 20 from each side of the equation: 2x=180

Divide by 2: x=90

The first number is 90, the second number is 110.

Hope this helps!

Explain why a sample of 30 dentists from a large city taken to estimate the median income of all residents of that large city is not representative

Answers

Answer: Because all individuals in the sample have the same job, so the sample is biased.

Step-by-step explanation:

Ignoring the fact that 30 is a small sample for a large city, we already know that all the people in the sample has the same profession.

Now, we can expect that two dentists win have around the same income, but not all the residents in the city are dentists

A lot of them work in fast food, others may be lawyers, others may be freelancers.

We have a lot of jobs where the income does not coincide with the average income of a dentist, so with the sample of 30 dentists we are not actually representing all the other possible jobs that there are in the city.

If we want a sample that represents the income of all the residents, we should have a random sample (so the sample is not biased, like in this case).

In a group of 42 students, 9 study both Art and Biology.
10 study Biology but not Art.
7 study neither subject.
Given that a randomly selected student studies Art, what is the probability the student studies Art and Biology?

Answers

Answer:

The probability the student studies Art and Biology is 0.2143.

Step-by-step explanation:

Denote the events as follows:

A = a students studies Art

B = a students studies Biology

The information provided is:

N = 42

n (A ∩ B) = 9

n (A' ∩ B) = 10

n (A' ∩ B') = 7

Then the number of students who study Art but not Biology is:

n (A ∩ B') = N - n (A ∩ B) - n (A' ∩ B) - n (A' ∩ B')

               [tex]=42-10-7-9\\\\=16[/tex]

The number of students who study Art but not Biology is 16.

Compute the probability the student studies Art and Biology as follows:

[tex]P(A\cap B)=\frac{n (A\cap B)}{N}[/tex]

               [tex]=\frac{9}{42}\\\\=\frac{3}{14}\\\\=0.2143[/tex]

Thus, the probability the student studies Art and Biology is 0.2143.

Lianne drew a sphere with a radius of 7 in. She calculated its volume and wrote it below.

Answers

volume = 1436.76 inches

Answer:

1372

Step-by-step explanation:

4x7x7x7=1372:v=4/3 pi r^3

Therefore, 1372 is the value that should be multiplied by Pi in the numerator to correctly show the volume of the sphere.

please mark me brainliest :)

Hhhhhhheeeeelllllpppppppp

Answers

Answer:

tan 41 = 0.87

sin 63 = 0.89

cos 14 = 0.97

Step-by-step explanation:

No explanation since the question states to use the ALEKS calculator so you just make sure the calculator is in degrees then simply press tan 41 etc.

What is the value of p?

Answers

Answer:

[tex]p = 43 \: \: \: degrees[/tex]

Answer A is correct

Step-by-step explanation:

[tex]90 + p = 133[/tex]

the sum of the exterior angles in a triangle is equal to the sum of opposite interior angles.

[tex]p = 133 - 90 \\ p =4 3 \: \: \: degrees[/tex]

hope this helps

brainliest appreciated

good luck! have a nice day!

Harry is half his brother's age. His brother is 28 years younger than their Aunt Jenny, who is five years older than Harry and his brother's dad. their dad is 31 years old. how old is Harry?

Answers

Answer:

4 years old

Step-by-step explanation:

Harry = H

Brother = B

Aunty = A

Dad = B

H = ½ B

B = A - 28

A = D + 5

D = 31

A = 31 + 5 = 36

B = 36 -28 = 8 years old

H = ½ . 8 = 4 years old

HELPPPP ME PLZZZZ!!!!!!

Answers

Answers:

14.  Each leg is   [tex]21\sqrt{2}[/tex]  units long.

15 (a). The longer leg is [tex]7\sqrt{3}[/tex]  units long

15 (b). The hypotenuse is [tex]14[/tex] units long

=====================================================

Explanations:

For a 45 degree right triangle, aka 45-45-90 triangle, the hypotenuse is equal to sqrt(2) times the short leg. Algebraically we can say

[tex]y = x\sqrt{2}[/tex] where x is the leg and y is the hypotenuse

Let's solve for x

[tex]y = x\sqrt{2}\\\\x\sqrt{2} = y\\\\x = \frac{y}{\sqrt{2}}\\\\x = \frac{y\sqrt{2}}{\sqrt{2}*\sqrt{2}} \ \text{rationalizing denominator}\\\\x = \frac{y\sqrt{2}}{2}\\\\[/tex]

Now plug in the given hypotenuse y = 42, this leads to,

[tex]x = \frac{y\sqrt{2}}{2}\\\\x = \frac{42\sqrt{2}}{2}\\\\x = \frac{42}{2}\sqrt{2}\\\\x = 21\sqrt{2}\\\\[/tex]

---------------------------

For a 30-60-90 triangle, the hypotenuse is double that of the short leg. So the hypotenuse is 2*7 = 14.

The longer leg is equal to sqrt(3) times the short leg. The longer leg is [tex]7\sqrt{3}[/tex]

$49 per month for unlimited calling plus 5 cents for each text message. Is this proportional or non proportional?

Answers

Answer: proptional

Step-by-step explanation:

Given the function ƒ(x) = 8x^2 − 14x − 10, find ƒ(−2). A) ƒ(−2) = 50 B) ƒ(−2) = 60 C) ƒ(−2) = −6 D) ƒ(−2) = −70

Answers

Answer:

50

Step-by-step explanation:

f(x) = 8x² - 14x - 10

f(-2) = 8(-2)² - 14(-2) -10

f(-2) 8*4 + 28 - 10

f(-2) = 32 + 28 - 10 = 50

Select all that apply.
Which of the following name a line in the drawings



Answers

DB is the answer that your looking for

Answer:

DB

It's the only line that is not a segment.

Step-by-step explanation:

A box contains 5 yellow balls, 3 blue, and 1 red ball. Two balls are drawn at random. Find the probability that the two balls are yellow

Answers

Answer:

5/18

Step-by-step explanation:

5/9 times 1/2

5/18

I may be wrong sorry

Pentagon A B C D E is reflected across the line of reflection m to pentagon A prime B prime C prime D prime E prime. Pentagon A prime B prime C prime D prime E prime is rotated about point C prime 180 degrees clockwise. Which rule describes the composition of transformations that maps figure ABCDE to figure A"B"C'D"E"? 90 degree rotation about point C prime composition reflected across line m Reflected across line m composition 90 degree rotation about point C prime 180 degree rotation about point C prime composition reflected across line m Reflected across line m composition 180 degree rotation about point C prim

Answers

Answer: It’s C i got it right on the test

Step-by-step explanation:

RC’ ,180 o r m

Answer:

It's C I got a 100 on the test

Step-by-step explanation:

A and B have to be wrong because there is no 90° rotation and D isn't right because it's backwards

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