Adam pays $18.70 for 1 marble and 6 stickers.
The marble costs $2.60 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 + 2.60
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 2.60 + 6 u
= 7 u + 2.60
7 u + 2.60 = 18.70
7 u = 18.70 - 2.60
7 u = 16.10
1 u = 16.10 ÷ 7 = 2.30
Cost of 1 marble
= 2.30 + 2.60
= $4.90
(b)
Cost of 6 marbles and 5 stickers
= 6 x 4.90 + 5 x 2.30
= 29.40 + 11.50
= $40.90
Answer(s): (a) $4.90; (b) $40.90