Adam pays $42.40 for 1 marble and 6 stickers.
The marble costs $2.50 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 6 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 + 2.50
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 2.50 + 6 u
= 7 u + 2.50
7 u + 2.50 = 42.40
7 u = 42.40 - 2.50
7 u = 39.90
1 u = 39.90 ÷ 7 = 5.70
Cost of 1 marble
= 5.70 + 2.50
= $8.20
(b)
Cost of 6 marbles and 5 stickers
= 6 x 8.20 + 5 x 5.70
= 49.20 + 28.50
= $77.70
Answer(s): (a) $8.20; (b) $77.70