Adam pays $16.20 for 1 marble and 7 stickers.
The marble costs $2.60 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 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 + 2.60
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 2.60 + 7 u
= 8 u + 2.60
8 u + 2.60 = 16.20
8 u = 16.20 - 2.60
8 u = 13.60
1 u = 13.60 ÷ 8 = 1.70
Cost of 1 marble
= 1.70 + 2.60
= $4.30
(b)
Cost of 7 marbles and 8 stickers
= 7 x 4.30 + 8 x 1.70
= 30.10 + 13.60
= $43.70
Answer(s): (a) $4.30; (b) $43.70