Adam pays $34.20 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 4 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 = 34.20
9 u = 34.20 - 1.80
9 u = 32.40
1 u = 32.40 ÷ 9 = 3.60
Cost of 1 marble
= 3.60 + 1.80
= $5.40
(b)
Cost of 8 marbles and 4 stickers
= 8 x 5.40 + 4 x 3.60
= 43.20 + 14.40
= $57.60
Answer(s): (a) $5.40; (b) $57.60