Adam pays $27.90 for 1 marble and 8 stickers.
The marble costs $2.70 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 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 + 2.70
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 2.70 + 8 u
= 9 u + 2.70
9 u + 2.70 = 27.90
9 u = 27.90 - 2.70
9 u = 25.20
1 u = 25.20 ÷ 9 = 2.80
Cost of 1 marble
= 2.80 + 2.70
= $5.50
(b)
Cost of 8 marbles and 3 stickers
= 8 x 5.50 + 3 x 2.80
= 44.00 + 8.40
= $52.40
Answer(s): (a) $5.50; (b) $52.40