Adam pays $26.80 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 3 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 = 26.80
8 u = 26.80 - 1.20
8 u = 25.60
1 u = 25.60 ÷ 8 = 3.20
Cost of 1 marble
= 3.20 + 1.20
= $4.40
(b)
Cost of 7 marbles and 3 stickers
= 7 x 4.40 + 3 x 3.20
= 30.80 + 9.60
= $40.40
Answer(s): (a) $4.40; (b) $40.40