Adam pays $39.50 for 1 marble and 6 stickers.
The marble costs $2.40 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 6 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 + 2.40
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 2.40 + 6 u
= 7 u + 2.40
7 u + 2.40 = 39.50
7 u = 39.50 - 2.40
7 u = 37.10
1 u = 37.10 ÷ 7 = 5.30
Cost of 1 marble
= 5.30 + 2.40
= $7.70
(b)
Cost of 6 marbles and 3 stickers
= 6 x 7.70 + 3 x 5.30
= 46.20 + 15.90
= $62.10
Answer(s): (a) $7.70; (b) $62.10