Adam pays $19.10 for 1 marble and 4 stickers.
The marble costs $1.60 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 4 marbles and 7 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 4 stickers
= 4 x 1 u
= 4 u
Total cost of 1 marble and 4 stickers
= 1 u + 1.60 + 4 u
= 5 u + 1.60
5 u + 1.60 = 19.10
5 u = 19.10 - 1.60
5 u = 17.50
1 u = 17.50 ÷ 5 = 3.50
Cost of 1 marble
= 3.50 + 1.60
= $5.10
(b)
Cost of 4 marbles and 7 stickers
= 4 x 5.10 + 7 x 3.50
= 20.40 + 24.50
= $44.90
Answer(s): (a) $5.10; (b) $44.90