Adam pays $28.80 for 1 marble and 7 stickers.
The marble costs $2.40 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 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 + 2.40
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 2.40 + 7 u
= 8 u + 2.40
8 u + 2.40 = 28.80
8 u = 28.80 - 2.40
8 u = 26.40
1 u = 26.40 ÷ 8 = 3.30
Cost of 1 marble
= 3.30 + 2.40
= $5.70
(b)
Cost of 7 marbles and 6 stickers
= 7 x 5.70 + 6 x 3.30
= 39.90 + 19.80
= $59.70
Answer(s): (a) $5.70; (b) $59.70