Adam pays $40.20 for 1 marble and 4 stickers.
The marble costs $2.70 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 + 2.70
Cost of 4 stickers
= 4 x 1 u
= 4 u
Total cost of 1 marble and 4 stickers
= 1 u + 2.70 + 4 u
= 5 u + 2.70
5 u + 2.70 = 40.20
5 u = 40.20 - 2.70
5 u = 37.50
1 u = 37.50 ÷ 5 = 7.50
Cost of 1 marble
= 7.50 + 2.70
= $10.20
(b)
Cost of 4 marbles and 7 stickers
= 4 x 10.20 + 7 x 7.50
= 40.80 + 52.50
= $93.30
Answer(s): (a) $10.20; (b) $93.30