Adam pays $37.90 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 2 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 = 37.90
9 u = 37.90 - 2.80
9 u = 35.10
1 u = 35.10 ÷ 9 = 3.90
Cost of 1 marble
= 3.90 + 2.80
= $6.70
(b)
Cost of 8 marbles and 2 stickers
= 8 x 6.70 + 2 x 3.90
= 53.60 + 7.80
= $61.40
Answer(s): (a) $6.70; (b) $61.40