Adam pays $21.50 for 1 marble and 6 stickers.
The marble costs $2.60 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 + 2.60
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 2.60 + 6 u
= 7 u + 2.60
7 u + 2.60 = 21.50
7 u = 21.50 - 2.60
7 u = 18.90
1 u = 18.90 ÷ 7 = 2.70
Cost of 1 marble
= 2.70 + 2.60
= $5.30
(b)
Cost of 6 marbles and 7 stickers
= 6 x 5.30 + 7 x 2.70
= 31.80 + 18.90
= $50.70
Answer(s): (a) $5.30; (b) $50.70