Adam pays $19.80 for 1 marble and 5 stickers.
The marble costs $1.20 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 5 marbles and 8 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.20
Cost of 5 stickers
= 5 x 1 u
= 5 u
Total cost of 1 marble and 5 stickers
= 1 u + 1.20 + 5 u
= 6 u + 1.20
6 u + 1.20 = 19.80
6 u = 19.80 - 1.20
6 u = 18.60
1 u = 18.60 ÷ 6 = 3.10
Cost of 1 marble
= 3.10 + 1.20
= $4.30
(b)
Cost of 5 marbles and 8 stickers
= 5 x 4.30 + 8 x 3.10
= 21.50 + 24.80
= $46.30
Answer(s): (a) $4.30; (b) $46.30