Adam pays $22.50 for 1 marble and 8 stickers.
The marble costs $1.80 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 marbles and 2 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.80
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 1.80 + 8 u
= 9 u + 1.80
9 u + 1.80 = 22.50
9 u = 22.50 - 1.80
9 u = 20.70
1 u = 20.70 ÷ 9 = 2.30
Cost of 1 marble
= 2.30 + 1.80
= $4.10
(b)
Cost of 8 marbles and 2 stickers
= 8 x 4.10 + 2 x 2.30
= 32.80 + 4.60
= $37.40
Answer(s): (a) $4.10; (b) $37.40