Adam pays $21.90 for 1 marble and 5 stickers.
The marble costs $1.50 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 5 marbles and 8 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 5 stickers
= 5 x 1 u
= 5 u
Total cost of 1 marble and 5 stickers
= 1 u + 1.50 + 5 u
= 6 u + 1.50
6 u + 1.50 = 21.90
6 u = 21.90 - 1.50
6 u = 20.40
1 u = 20.40 ÷ 6 = 3.40
Cost of 1 marble
= 3.40 + 1.50
= $4.90
(b)
Cost of 5 marbles and 8 stickers
= 5 x 4.90 + 8 x 3.40
= 24.50 + 27.20
= $51.70
Answer(s): (a) $4.90; (b) $51.70