Adam pays $41.90 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 = 41.90
9 u = 41.90 - 2.30
9 u = 39.60
1 u = 39.60 ÷ 9 = 4.40
Cost of 1 marble
= 4.40 + 2.30
= $6.70
(b)
Cost of 8 marbles and 7 stickers
= 8 x 6.70 + 7 x 4.40
= 53.60 + 30.80
= $84.40
Answer(s): (a) $6.70; (b) $84.40