Adam pays $33.60 for 1 marble and 6 stickers.
The marble costs $2.80 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 6 marbles and 8 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.80
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 2.80 + 6 u
= 7 u + 2.80
7 u + 2.80 = 33.60
7 u = 33.60 - 2.80
7 u = 30.80
1 u = 30.80 ÷ 7 = 4.40
Cost of 1 marble
= 4.40 + 2.80
= $7.20
(b)
Cost of 6 marbles and 8 stickers
= 6 x 7.20 + 8 x 4.40
= 43.20 + 35.20
= $78.40
Answer(s): (a) $7.20; (b) $78.40