Adam pays $32.90 for 1 marble and 5 stickers.
The marble costs $1.70 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 5 marbles and 7 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 5 stickers
= 5 x 1 u
= 5 u
Total cost of 1 marble and 5 stickers
= 1 u + 1.70 + 5 u
= 6 u + 1.70
6 u + 1.70 = 32.90
6 u = 32.90 - 1.70
6 u = 31.20
1 u = 31.20 ÷ 6 = 5.20
Cost of 1 marble
= 5.20 + 1.70
= $6.90
(b)
Cost of 5 marbles and 7 stickers
= 5 x 6.90 + 7 x 5.20
= 34.50 + 36.40
= $70.90
Answer(s): (a) $6.90; (b) $70.90