At a bookstore, Jonathan paid $15 for 1 story book and 2 textbooks. The story book cost $6 more than the total cost of all the textbooks.
- How much did 1 story book cost?
- How much did 1 textbook cost?
(a)
Cost of 2 textbooks = 1 u
Cost of 1 story book = 1 u + 6
Total cost of 2 textbooks and 1 story book
= 1 u + 1 u + 6
= 2 u + 6
2 u + 6 = 15
2 u = 15 - 6
2 u = 9
1 u = 9 ÷ 2 = 4.50
Cost of 1 story book
= 1 u + 6
= 4.50 + 6
= $10.50
(b)
Cost of 2 textbooks = $4.50
Cost of 1 textbook
= 4.50 ÷ 2
= $2.25
Answer(s): (a) $10.50; (b) $2.25