Adam pays $36.40 for 1 marble and 7 stickers.
The marble costs $1.20 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 8 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 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 1.20 + 7 u
= 8 u + 1.20
8 u + 1.20 = 36.40
8 u = 36.40 - 1.20
8 u = 35.20
1 u = 35.20 ÷ 8 = 4.40
Cost of 1 marble
= 4.40 + 1.20
= $5.60
(b)
Cost of 7 marbles and 8 stickers
= 7 x 5.60 + 8 x 4.40
= 39.20 + 35.20
= $74.40
Answer(s): (a) $5.60; (b) $74.40