Adam pays $44.80 for 1 marble and 8 stickers.
The marble costs $2.50 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 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 + 2.50
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 2.50 + 8 u
= 9 u + 2.50
9 u + 2.50 = 44.80
9 u = 44.80 - 2.50
9 u = 42.30
1 u = 42.30 ÷ 9 = 4.70
Cost of 1 marble
= 4.70 + 2.50
= $7.20
(b)
Cost of 8 marbles and 7 stickers
= 8 x 7.20 + 7 x 4.70
= 57.60 + 32.90
= $90.50
Answer(s): (a) $7.20; (b) $90.50