Adam pays $30.30 for 1 marble and 7 stickers.
The marble costs $1.50 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 6 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.50
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 1.50 + 7 u
= 8 u + 1.50
8 u + 1.50 = 30.30
8 u = 30.30 - 1.50
8 u = 28.80
1 u = 28.80 ÷ 8 = 3.60
Cost of 1 marble
= 3.60 + 1.50
= $5.10
(b)
Cost of 7 marbles and 6 stickers
= 7 x 5.10 + 6 x 3.60
= 35.70 + 21.60
= $57.30
Answer(s): (a) $5.10; (b) $57.30