Adam pays $30.40 for 1 marble and 6 stickers.
The marble costs $1.70 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 + 1.70
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 1.70 + 6 u
= 7 u + 1.70
7 u + 1.70 = 30.40
7 u = 30.40 - 1.70
7 u = 28.70
1 u = 28.70 ÷ 7 = 4.10
Cost of 1 marble
= 4.10 + 1.70
= $5.80
(b)
Cost of 6 marbles and 8 stickers
= 6 x 5.80 + 8 x 4.10
= 34.80 + 32.80
= $67.60
Answer(s): (a) $5.80; (b) $67.60