Adam pays $28.90 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 5 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 = 28.90
9 u = 28.90 - 2.80
9 u = 26.10
1 u = 26.10 ÷ 9 = 2.90
Cost of 1 marble
= 2.90 + 2.80
= $5.70
(b)
Cost of 8 marbles and 5 stickers
= 8 x 5.70 + 5 x 2.90
= 45.60 + 14.50
= $60.10
Answer(s): (a) $5.70; (b) $60.10