Adam pays $42.40 for 1 marble and 8 stickers.
The marble costs $2.80 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 marbles and 2 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.80
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 2.80 + 8 u
= 9 u + 2.80
9 u + 2.80 = 42.40
9 u = 42.40 - 2.80
9 u = 39.60
1 u = 39.60 ÷ 9 = 4.40
Cost of 1 marble
= 4.40 + 2.80
= $7.20
(b)
Cost of 8 marbles and 2 stickers
= 8 x 7.20 + 2 x 4.40
= 57.60 + 8.80
= $66.40
Answer(s): (a) $7.20; (b) $66.40