Adam pays $21.10 for 1 marble and 4 stickers.
The marble costs $2.60 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 4 marbles and 7 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.60
Cost of 4 stickers
= 4 x 1 u
= 4 u
Total cost of 1 marble and 4 stickers
= 1 u + 2.60 + 4 u
= 5 u + 2.60
5 u + 2.60 = 21.10
5 u = 21.10 - 2.60
5 u = 18.50
1 u = 18.50 ÷ 5 = 3.70
Cost of 1 marble
= 3.70 + 2.60
= $6.30
(b)
Cost of 4 marbles and 7 stickers
= 4 x 6.30 + 7 x 3.70
= 25.20 + 25.90
= $51.10
Answer(s): (a) $6.30; (b) $51.10