Adam pays $17.50 for 1 marble and 7 stickers.
The marble costs $2.30 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 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 + 2.30
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 2.30 + 7 u
= 8 u + 2.30
8 u + 2.30 = 17.50
8 u = 17.50 - 2.30
8 u = 15.20
1 u = 15.20 ÷ 8 = 1.90
Cost of 1 marble
= 1.90 + 2.30
= $4.20
(b)
Cost of 7 marbles and 8 stickers
= 7 x 4.20 + 8 x 1.90
= 29.40 + 15.20
= $44.60
Answer(s): (a) $4.20; (b) $44.60