Adam pays $19.80 for 1 marble and 6 stickers.
The marble costs $1.60 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 6 marbles and 2 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 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 1.60 + 6 u
= 7 u + 1.60
7 u + 1.60 = 19.80
7 u = 19.80 - 1.60
7 u = 18.20
1 u = 18.20 ÷ 7 = 2.60
Cost of 1 marble
= 2.60 + 1.60
= $4.20
(b)
Cost of 6 marbles and 2 stickers
= 6 x 4.20 + 2 x 2.60
= 25.20 + 5.20
= $30.40
Answer(s): (a) $4.20; (b) $30.40