Adam pays $18.40 for 1 marble and 5 stickers.
The marble costs $2.80 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 5 marbles and 3 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.80
Cost of 5 stickers
= 5 x 1 u
= 5 u
Total cost of 1 marble and 5 stickers
= 1 u + 2.80 + 5 u
= 6 u + 2.80
6 u + 2.80 = 18.40
6 u = 18.40 - 2.80
6 u = 15.60
1 u = 15.60 ÷ 6 = 2.60
Cost of 1 marble
= 2.60 + 2.80
= $5.40
(b)
Cost of 5 marbles and 3 stickers
= 5 x 5.40 + 3 x 2.60
= 27.00 + 7.80
= $34.80
Answer(s): (a) $5.40; (b) $34.80