Adam pays $23.20 for 1 marble and 6 stickers.
The marble costs $2.90 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 6 marbles and 7 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.90
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 2.90 + 6 u
= 7 u + 2.90
7 u + 2.90 = 23.20
7 u = 23.20 - 2.90
7 u = 20.30
1 u = 20.30 ÷ 7 = 2.90
Cost of 1 marble
= 2.90 + 2.90
= $5.80
(b)
Cost of 6 marbles and 7 stickers
= 6 x 5.80 + 7 x 2.90
= 34.80 + 20.30
= $55.10
Answer(s): (a) $5.80; (b) $55.10