Adam pays $36.80 for 1 marble and 6 stickers.
The marble costs $2.50 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 6 marbles and 3 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.50
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 2.50 + 6 u
= 7 u + 2.50
7 u + 2.50 = 36.80
7 u = 36.80 - 2.50
7 u = 34.30
1 u = 34.30 ÷ 7 = 4.90
Cost of 1 marble
= 4.90 + 2.50
= $7.40
(b)
Cost of 6 marbles and 3 stickers
= 6 x 7.40 + 3 x 4.90
= 44.40 + 14.70
= $59.10
Answer(s): (a) $7.40; (b) $59.10