# Dylan loves reading. He went to buy books from a bookstore. A school bag and 3 books cost \$180. A school bag and 5 books cost \$270

Question

Dylan loves reading. He went to buy books from a bookstore. A school bag and 3 books cost \$180. A school bag and 5 books cost \$270. How much did each book cost?

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4 weeks 2023-01-14T17:49:24+00:00 2 Answers 0 views 0

Each book costed 45\$.
Step-by-step explanation:
Let x represent the price of a school bag and y represent the price of a book.
we get the following system of equations:
x+3y=180  (equation 1)
x+5y=270 (equation 2)
using equation 1: x=180-3y
then we substitute x in equation 2 in order to find y:
180-3y+5y=270
180+2y=270
2y=270-180=90
y=90/2=45
and we know that y represents the price of a book, so each book costs 45\$.

2. School bag _ y
book _ x
system:
y+3x=180
y+5x=270
y=180-3x (and we put that instead of ‘y’ in the second equation)
(180-3x)+5x=270
180+2x=270
2x=90
x=45
so one book costs \$45
and school bag:
y+3×45=180
y+135=180
y=180-135
y=45