Adam pays $39.50 for 1 marble and 8 stickers.
The marble costs $2.60 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 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 + 2.60
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 2.60 + 8 u
= 9 u + 2.60
9 u + 2.60 = 39.50
9 u = 39.50 - 2.60
9 u = 36.90
1 u = 36.90 ÷ 9 = 4.10
Cost of 1 marble
= 4.10 + 2.60
= $6.70
(b)
Cost of 8 marbles and 6 stickers
= 8 x 6.70 + 6 x 4.10
= 53.60 + 24.60
= $78.20
Answer(s): (a) $6.70; (b) $78.20