Adam pays $21.70 for 1 marble and 6 stickers.
The marble costs $1.40 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 + 1.40
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 1.40 + 6 u
= 7 u + 1.40
7 u + 1.40 = 21.70
7 u = 21.70 - 1.40
7 u = 20.30
1 u = 20.30 ÷ 7 = 2.90
Cost of 1 marble
= 2.90 + 1.40
= $4.30
(b)
Cost of 6 marbles and 5 stickers
= 6 x 4.30 + 5 x 2.90
= 25.80 + 14.50
= $40.30
Answer(s): (a) $4.30; (b) $40.30