Adam pays $18.30 for 1 marble and 8 stickers.
The marble costs $1.20 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 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 + 1.20
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 1.20 + 8 u
= 9 u + 1.20
9 u + 1.20 = 18.30
9 u = 18.30 - 1.20
9 u = 17.10
1 u = 17.10 ÷ 9 = 1.90
Cost of 1 marble
= 1.90 + 1.20
= $3.10
(b)
Cost of 8 marbles and 4 stickers
= 8 x 3.10 + 4 x 1.90
= 24.80 + 7.60
= $32.40
Answer(s): (a) $3.10; (b) $32.40