Adam pays $15.90 for 1 marble and 8 stickers.
The marble costs $1.50 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 marbles and 6 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.50
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 1.50 + 8 u
= 9 u + 1.50
9 u + 1.50 = 15.90
9 u = 15.90 - 1.50
9 u = 14.40
1 u = 14.40 ÷ 9 = 1.60
Cost of 1 marble
= 1.60 + 1.50
= $3.10
(b)
Cost of 8 marbles and 6 stickers
= 8 x 3.10 + 6 x 1.60
= 24.80 + 9.60
= $34.40
Answer(s): (a) $3.10; (b) $34.40