Adam pays $27.80 for 1 marble and 7 stickers.
The marble costs $2.20 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 4 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.20
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 2.20 + 7 u
= 8 u + 2.20
8 u + 2.20 = 27.80
8 u = 27.80 - 2.20
8 u = 25.60
1 u = 25.60 ÷ 8 = 3.20
Cost of 1 marble
= 3.20 + 2.20
= $5.40
(b)
Cost of 7 marbles and 4 stickers
= 7 x 5.40 + 4 x 3.20
= 37.80 + 12.80
= $50.60
Answer(s): (a) $5.40; (b) $50.60