Adam pays $25.80 for 1 marble and 7 stickers.
The marble costs $2.60 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 2 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.60
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 2.60 + 7 u
= 8 u + 2.60
8 u + 2.60 = 25.80
8 u = 25.80 - 2.60
8 u = 23.20
1 u = 23.20 ÷ 8 = 2.90
Cost of 1 marble
= 2.90 + 2.60
= $5.50
(b)
Cost of 7 marbles and 2 stickers
= 7 x 5.50 + 2 x 2.90
= 38.50 + 5.80
= $44.30
Answer(s): (a) $5.50; (b) $44.30