Adam pays $20.50 for 1 marble and 8 stickers.
The marble costs $1.60 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 + 1.60
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 1.60 + 8 u
= 9 u + 1.60
9 u + 1.60 = 20.50
9 u = 20.50 - 1.60
9 u = 18.90
1 u = 18.90 ÷ 9 = 2.10
Cost of 1 marble
= 2.10 + 1.60
= $3.70
(b)
Cost of 8 marbles and 2 stickers
= 8 x 3.70 + 2 x 2.10
= 29.60 + 4.20
= $33.80
Answer(s): (a) $3.70; (b) $33.80