Adam pays $36.30 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 7 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 = 36.30
9 u = 36.30 - 1.20
9 u = 35.10
1 u = 35.10 ÷ 9 = 3.90
Cost of 1 marble
= 3.90 + 1.20
= $5.10
(b)
Cost of 8 marbles and 7 stickers
= 8 x 5.10 + 7 x 3.90
= 40.80 + 27.30
= $68.10
Answer(s): (a) $5.10; (b) $68.10