SOLUTION: Chris spent $45 buying 12 books to donate to the local elementary school. Activity books cost $2 each and story books cost $9 each, how many of each type of book did Chris purchase

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Chris spent $45 buying 12 books to donate to the local elementary school. Activity books cost $2 each and story books cost $9 each, how many of each type of book did Chris purchase      Log On


   

Question 1099148: Chris spent $45 buying 12 books to donate to the local elementary school. Activity books cost $2 each and story books cost $9 each, how many of each type of book did Chris purchase?
Answer by ikleyn(52803) About Me  (Show Source):
You can put this solution on YOUR website!
.
Let A be the number of activity books.

Then the number of story books is (12-A).

The "money" equation is

2A + 9*(12-A) = 45    dollars.   (Counting A-books at 2 dollars and story-books at 9 dollars)

Simplify and solve for A:

2A + 108 - 9A = 45  ====>  -7A = 45 - 108 = - 63   ====>  A = %28-63%29%2F%28-7%29 = 9.


Answer.  Chris purchased 9 activity books and 12-9 = 3 story books.