Adam pays $36.10 for 1 marble and 8 stickers.
The marble costs $2.80 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 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 + 2.80
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 2.80 + 8 u
= 9 u + 2.80
9 u + 2.80 = 36.10
9 u = 36.10 - 2.80
9 u = 33.30
1 u = 33.30 ÷ 9 = 3.70
Cost of 1 marble
= 3.70 + 2.80
= $6.50
(b)
Cost of 8 marbles and 3 stickers
= 8 x 6.50 + 3 x 3.70
= 52.00 + 11.10
= $63.10
Answer(s): (a) $6.50; (b) $63.10