Adam pays $33.80 for 1 marble and 5 stickers.
The marble costs $2.60 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 5 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 5 stickers
= 5 x 1 u
= 5 u
Total cost of 1 marble and 5 stickers
= 1 u + 2.60 + 5 u
= 6 u + 2.60
6 u + 2.60 = 33.80
6 u = 33.80 - 2.60
6 u = 31.20
1 u = 31.20 ÷ 6 = 5.20
Cost of 1 marble
= 5.20 + 2.60
= $7.80
(b)
Cost of 5 marbles and 7 stickers
= 5 x 7.80 + 7 x 5.20
= 39.00 + 36.40
= $75.40
Answer(s): (a) $7.80; (b) $75.40