Adam pays $36.90 for 1 marble and 5 stickers.
The marble costs $2.70 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 5 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 + 2.70
Cost of 5 stickers
= 5 x 1 u
= 5 u
Total cost of 1 marble and 5 stickers
= 1 u + 2.70 + 5 u
= 6 u + 2.70
6 u + 2.70 = 36.90
6 u = 36.90 - 2.70
6 u = 34.20
1 u = 34.20 ÷ 6 = 5.70
Cost of 1 marble
= 5.70 + 2.70
= $8.40
(b)
Cost of 5 marbles and 7 stickers
= 5 x 8.40 + 7 x 5.70
= 42.00 + 39.90
= $81.90
Answer(s): (a) $8.40; (b) $81.90