a group of students washed cars to raise money... WORD PROBLEM

Question

A group of students washed cars to raise money. The net amount A, in dollars, raised by washing K cars is given by the function A(K)=4K-30. If the group washed 15 cars, what is the net amount they raised?

Answer 1

Hi Annie,

First, note that A(K) means that there is a function A which represents the net amount of money, in dollars, raised in terms of the number of cars washed (K).

So if the group washed 15 cars, then K=15.

Thus, given that   A(K)= 4K - 30   and   K= 15 ,   we are looking to solve for A(15) ...

A(15) = 4(15) - 30 = 60 - 30 = 30

Therefore, if the group washed 15 cars, then they raised a net amount of $30.

 

Answer 2

Well since K represents cars, and you know they washed 15 cars, you also know that K = 15 in this problem.

The amount, A, then is: A(15) = 4(15) - 30 = 60 - 30 = 30. So they raised $30.
In this case A(K) does NOT mean to multiply A by K. it just means that to find A, we need to use K - the amount they raised depends on how many cars they washed.