Adam pays $19.70 for 1 marble and 6 stickers.
The marble costs $2.20 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 + 2.20
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 2.20 + 6 u
= 7 u + 2.20
7 u + 2.20 = 19.70
7 u = 19.70 - 2.20
7 u = 17.50
1 u = 17.50 ÷ 7 = 2.50
Cost of 1 marble
= 2.50 + 2.20
= $4.70
(b)
Cost of 6 marbles and 5 stickers
= 6 x 4.70 + 5 x 2.50
= 28.20 + 12.50
= $40.70
Answer(s): (a) $4.70; (b) $40.70