Adam pays $39.10 for 1 marble and 8 stickers.
The marble costs $2.20 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 marbles and 5 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.20
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 2.20 + 8 u
= 9 u + 2.20
9 u + 2.20 = 39.10
9 u = 39.10 - 2.20
9 u = 36.90
1 u = 36.90 ÷ 9 = 4.10
Cost of 1 marble
= 4.10 + 2.20
= $6.30
(b)
Cost of 8 marbles and 5 stickers
= 8 x 6.30 + 5 x 4.10
= 50.40 + 20.50
= $70.90
Answer(s): (a) $6.30; (b) $70.90