Adam pays $34.20 for 1 marble and 6 stickers.
The marble costs $2.70 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 + 2.70
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 2.70 + 6 u
= 7 u + 2.70
7 u + 2.70 = 34.20
7 u = 34.20 - 2.70
7 u = 31.50
1 u = 31.50 ÷ 7 = 4.50
Cost of 1 marble
= 4.50 + 2.70
= $7.20
(b)
Cost of 6 marbles and 8 stickers
= 6 x 7.20 + 8 x 4.50
= 43.20 + 36.00
= $79.20
Answer(s): (a) $7.20; (b) $79.20