Adam pays $28.50 for 1 marble and 6 stickers.
The marble costs $1.90 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 + 1.90
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 1.90 + 6 u
= 7 u + 1.90
7 u + 1.90 = 28.50
7 u = 28.50 - 1.90
7 u = 26.60
1 u = 26.60 ÷ 7 = 3.80
Cost of 1 marble
= 3.80 + 1.90
= $5.70
(b)
Cost of 6 marbles and 8 stickers
= 6 x 5.70 + 8 x 3.80
= 34.20 + 30.40
= $64.60
Answer(s): (a) $5.70; (b) $64.60