Adam pays $39.20 for 1 marble and 8 stickers.
The marble costs $1.40 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 marbles and 3 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.40
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 1.40 + 8 u
= 9 u + 1.40
9 u + 1.40 = 39.20
9 u = 39.20 - 1.40
9 u = 37.80
1 u = 37.80 ÷ 9 = 4.20
Cost of 1 marble
= 4.20 + 1.40
= $5.60
(b)
Cost of 8 marbles and 3 stickers
= 8 x 5.60 + 3 x 4.20
= 44.80 + 12.60
= $57.40
Answer(s): (a) $5.60; (b) $57.40