Adam pays $23.50 for 1 marble and 7 stickers.
The marble costs $2.70 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 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 + 2.70
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 2.70 + 7 u
= 8 u + 2.70
8 u + 2.70 = 23.50
8 u = 23.50 - 2.70
8 u = 20.80
1 u = 20.80 ÷ 8 = 2.60
Cost of 1 marble
= 2.60 + 2.70
= $5.30
(b)
Cost of 7 marbles and 2 stickers
= 7 x 5.30 + 2 x 2.60
= 37.10 + 5.20
= $42.30
Answer(s): (a) $5.30; (b) $42.30