Adam pays $39.50 for 1 marble and 6 stickers.
The marble costs $1.70 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 6 marbles and 8 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.70
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 1.70 + 6 u
= 7 u + 1.70
7 u + 1.70 = 39.50
7 u = 39.50 - 1.70
7 u = 37.80
1 u = 37.80 ÷ 7 = 5.40
Cost of 1 marble
= 5.40 + 1.70
= $7.10
(b)
Cost of 6 marbles and 8 stickers
= 6 x 7.10 + 8 x 5.40
= 42.60 + 43.20
= $85.80
Answer(s): (a) $7.10; (b) $85.80