Algebra word problem

Question

15 books cost $51.25. Some were priced at $2.25 each,and the rest of the books were sold at $4.75. How many books were purchased at each price ?

Answer 1

Hi Joshua,

 

First figure out what you are tryng to find:

Number of $2.25 books

Number of $4.75 books

 

Pick variables to represent those unknowns.

x = number of $2.25 books

y = number of $4.75 books

 

Write equations from the given information:

 

x + y = 15

2.25x + 4.75y = 51.25

 

from 1st equation: y = 15-x

Substitute into 2nd equation

 

2.25x + 4.75(15-x) = 51.25

2.25x + 71.25 - 4.75x = 51.25

-2.5x = -20

x = 8 of the $2.25 books

y = 7 of the $4.75 books

 

Questions?