Adam pays $30.40 for 1 marble and 7 stickers.
The marble costs $1.60 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 2 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.60
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 1.60 + 7 u
= 8 u + 1.60
8 u + 1.60 = 30.40
8 u = 30.40 - 1.60
8 u = 28.80
1 u = 28.80 ÷ 8 = 3.60
Cost of 1 marble
= 3.60 + 1.60
= $5.20
(b)
Cost of 7 marbles and 2 stickers
= 7 x 5.20 + 2 x 3.60
= 36.40 + 7.20
= $43.60
Answer(s): (a) $5.20; (b) $43.60