Adam pays $23.10 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 4 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 = 23.10
8 u = 23.10 - 1.50
8 u = 21.60
1 u = 21.60 ÷ 8 = 2.70
Cost of 1 marble
= 2.70 + 1.50
= $4.20
(b)
Cost of 7 marbles and 4 stickers
= 7 x 4.20 + 4 x 2.70
= 29.40 + 10.80
= $40.20
Answer(s): (a) $4.20; (b) $40.20