Adam pays $42.10 for 1 marble and 6 stickers.
The marble costs $2.20 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 6 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 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 2.20 + 6 u
= 7 u + 2.20
7 u + 2.20 = 42.10
7 u = 42.10 - 2.20
7 u = 39.90
1 u = 39.90 ÷ 7 = 5.70
Cost of 1 marble
= 5.70 + 2.20
= $7.90
(b)
Cost of 6 marbles and 3 stickers
= 6 x 7.90 + 3 x 5.70
= 47.40 + 17.10
= $64.50
Answer(s): (a) $7.90; (b) $64.50