Adam pays $27.10 for 1 marble and 7 stickers.
The marble costs $1.50 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 3 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.50
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 1.50 + 7 u
= 8 u + 1.50
8 u + 1.50 = 27.10
8 u = 27.10 - 1.50
8 u = 25.60
1 u = 25.60 ÷ 8 = 3.20
Cost of 1 marble
= 3.20 + 1.50
= $4.70
(b)
Cost of 7 marbles and 3 stickers
= 7 x 4.70 + 3 x 3.20
= 32.90 + 9.60
= $42.50
Answer(s): (a) $4.70; (b) $42.50