Adam pays $29.70 for 1 marble and 4 stickers.
The marble costs $2.20 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 4 marbles and 3 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 4 stickers
= 4 x 1 u
= 4 u
Total cost of 1 marble and 4 stickers
= 1 u + 2.20 + 4 u
= 5 u + 2.20
5 u + 2.20 = 29.70
5 u = 29.70 - 2.20
5 u = 27.50
1 u = 27.50 ÷ 5 = 5.50
Cost of 1 marble
= 5.50 + 2.20
= $7.70
(b)
Cost of 4 marbles and 3 stickers
= 4 x 7.70 + 3 x 5.50
= 30.80 + 16.50
= $47.30
Answer(s): (a) $7.70; (b) $47.30