Adam pays $37.40 for 1 marble and 8 stickers.
The marble costs $2.30 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 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 + 2.30
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 2.30 + 8 u
= 9 u + 2.30
9 u + 2.30 = 37.40
9 u = 37.40 - 2.30
9 u = 35.10
1 u = 35.10 ÷ 9 = 3.90
Cost of 1 marble
= 3.90 + 2.30
= $6.20
(b)
Cost of 8 marbles and 7 stickers
= 8 x 6.20 + 7 x 3.90
= 49.60 + 27.30
= $76.90
Answer(s): (a) $6.20; (b) $76.90