Adam pays $26.40 for 1 marble and 7 stickers.
The marble costs $1.60 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 5 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.60
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 1.60 + 7 u
= 8 u + 1.60
8 u + 1.60 = 26.40
8 u = 26.40 - 1.60
8 u = 24.80
1 u = 24.80 ÷ 8 = 3.10
Cost of 1 marble
= 3.10 + 1.60
= $4.70
(b)
Cost of 7 marbles and 5 stickers
= 7 x 4.70 + 5 x 3.10
= 32.90 + 15.50
= $48.40
Answer(s): (a) $4.70; (b) $48.40