Adam pays $23.70 for 1 marble and 8 stickers.
The marble costs $2.10 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 marbles and 6 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.10
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 2.10 + 8 u
= 9 u + 2.10
9 u + 2.10 = 23.70
9 u = 23.70 - 2.10
9 u = 21.60
1 u = 21.60 ÷ 9 = 2.40
Cost of 1 marble
= 2.40 + 2.10
= $4.50
(b)
Cost of 8 marbles and 6 stickers
= 8 x 4.50 + 6 x 2.40
= 36.00 + 14.40
= $50.40
Answer(s): (a) $4.50; (b) $50.40