Ask question

Ask question

All categories

3 years ago

12

The library sells 376 books at its annual used-book fundraiser. They take in a total of $2120. Childrens books cost $4, and adul

ts books cost $7. How many childrens books did they sell?
Let c = number of childrens books sold, and let a = the number of adult books sold.

which system of equations can the librarians use to solve this problem?

A. 4c+7a = 376
c+a = 2120
a= 376-c
B. 7c+4a = 2120
a+c = 376
C. 4a+7c=2120
c+a = 376
D. 4c + 7a = 2120

1 answer:

igomit [66]3 years ago

7 0

$Answer: \left\{\begin{array}{ccc}4a+7c=2120\\a+c=376\end{array}\right$

You might be interested in

Given the function f(x)=3^x, find the value of f^-1(27)

Shalnov [3]

This is asking you to solve the equation ...

... 27 = 3^x

You can use logarithms to find

... log(27) = x·log(3)

... log(27)/log(3) = x = 1.43136376.../0.47712125...

... x = 3

Or, you can use your knowledge of small cubes and match exponents.

... 3^3 = 3^x

... 3 = x

7 0

3 years ago

Marcus spent 2 hour reading,1 hour playing Rocket League,and took a 2 hour nap. What percent of the total time did he read?

Alona [7]

Answer: He read 40% of the total time.

Step-by-step explanation:

As per given,

Total time he spent = 2 +1+2 = 5 hours

Number of hours he spent on reading = 2 hours

The percent of the total time he read = $\dfrac{\text{Number of hours read}}{\text{Total time spent}}\times100$

$=\dfrac{2}{5}\times100\\\\=40\%$

i.e. The percent of the total time he read = 40%

Hence, he read 40% of the total time.

4 0

2 years ago

I need two equations to use elimination but I don't know what equations to use.

lyudmila [28]

2x+3y=160
-2x+7y=25 I hope that helps!!

7 0

2 years ago

Read 2 more answers

I need help please help me

barxatty [35]

Answer,

-5, 50/20, 2.43, 6

Step-by-step explanation:

the "5" and "6" are the square roots

3 0

2 years ago

Read 2 more answers

A circle has radius 50 cm. Which is closer to its area ?

SOVA2 [1]

Answer:

60

Step-by-step explanation:

That is the answer. Hope that helps

3 0

2 years ago