Question

A used book store sells paperback books for $4 each and hardback books for $6 each day. today they sold 40 books and made $180.

a. write a system equation to solve the problem


b. how many of each type of book was sold

Answer 1

a) x + y = 40

2x + 3y = 90

b) 30 paperback books and 10 hardback books

Explanation:

a) Let the number of paperback books be x and the number hardback books be y

Total number if books sold is 40

i.e x + y = 40

x costs $4 each and y costs $6 each

Total amount of books sold is $180

i.e 4x + 6y = 180

2( 2x + 3y) = 180

2x + 3y = 90

b) Solving the equations simultaneously,

x+y = 40 .. eq (1)

2x+3y = 90 .. eq(2)

Multiply eq(1) by 2

2x + 2y = 80 .. eq(3)

Subtract eq 3 from eq 2

y = 10

putting y as 10 in eq 1

x + 10 = 40

x= 30

Therefore, 30 paperback books and 10 hardback books were sold