Adam pays $31.30 for 1 marble and 5 stickers.
The marble costs $2.50 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 + 2.50
Cost of 5 stickers
= 5 x 1 u
= 5 u
Total cost of 1 marble and 5 stickers
= 1 u + 2.50 + 5 u
= 6 u + 2.50
6 u + 2.50 = 31.30
6 u = 31.30 - 2.50
6 u = 28.80
1 u = 28.80 ÷ 6 = 4.80
Cost of 1 marble
= 4.80 + 2.50
= $7.30
(b)
Cost of 5 marbles and 7 stickers
= 5 x 7.30 + 7 x 4.80
= 36.50 + 33.60
= $70.10
Answer(s): (a) $7.30; (b) $70.10