Adam pays $21.90 for 1 marble and 6 stickers.
The marble costs $1.60 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 6 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 + 1.60
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 1.60 + 6 u
= 7 u + 1.60
7 u + 1.60 = 21.90
7 u = 21.90 - 1.60
7 u = 20.30
1 u = 20.30 ÷ 7 = 2.90
Cost of 1 marble
= 2.90 + 1.60
= $4.50
(b)
Cost of 6 marbles and 8 stickers
= 6 x 4.50 + 8 x 2.90
= 27.00 + 23.20
= $50.20
Answer(s): (a) $4.50; (b) $50.20