Adam pays $38.20 for 1 marble and 6 stickers.
The marble costs $2.50 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 6 marbles and 8 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.50
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 2.50 + 6 u
= 7 u + 2.50
7 u + 2.50 = 38.20
7 u = 38.20 - 2.50
7 u = 35.70
1 u = 35.70 ÷ 7 = 5.10
Cost of 1 marble
= 5.10 + 2.50
= $7.60
(b)
Cost of 6 marbles and 8 stickers
= 6 x 7.60 + 8 x 5.10
= 45.60 + 40.80
= $86.40
Answer(s): (a) $7.60; (b) $86.40