Adam pays $24.90 for 1 marble and 7 stickers.
The marble costs $1.70 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 + 1.70
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 1.70 + 7 u
= 8 u + 1.70
8 u + 1.70 = 24.90
8 u = 24.90 - 1.70
8 u = 23.20
1 u = 23.20 ÷ 8 = 2.90
Cost of 1 marble
= 2.90 + 1.70
= $4.60
(b)
Cost of 7 marbles and 5 stickers
= 7 x 4.60 + 5 x 2.90
= 32.20 + 14.50
= $46.70
Answer(s): (a) $4.60; (b) $46.70