Adam pays $35.20 for 1 marble and 4 stickers.
The marble costs $1.70 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 4 marbles and 7 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.70
Cost of 4 stickers
= 4 x 1 u
= 4 u
Total cost of 1 marble and 4 stickers
= 1 u + 1.70 + 4 u
= 5 u + 1.70
5 u + 1.70 = 35.20
5 u = 35.20 - 1.70
5 u = 33.50
1 u = 33.50 ÷ 5 = 6.70
Cost of 1 marble
= 6.70 + 1.70
= $8.40
(b)
Cost of 4 marbles and 7 stickers
= 4 x 8.40 + 7 x 6.70
= 33.60 + 46.90
= $80.50
Answer(s): (a) $8.40; (b) $80.50