Adam pays $24.80 for 1 marble and 7 stickers.
The marble costs $2.40 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 6 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.40
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 2.40 + 7 u
= 8 u + 2.40
8 u + 2.40 = 24.80
8 u = 24.80 - 2.40
8 u = 22.40
1 u = 22.40 ÷ 8 = 2.80
Cost of 1 marble
= 2.80 + 2.40
= $5.20
(b)
Cost of 7 marbles and 6 stickers
= 7 x 5.20 + 6 x 2.80
= 36.40 + 16.80
= $53.20
Answer(s): (a) $5.20; (b) $53.20