Adam pays $30.30 for 1 marble and 5 stickers.
The marble costs $2.10 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 + 2.10
Cost of 5 stickers
= 5 x 1 u
= 5 u
Total cost of 1 marble and 5 stickers
= 1 u + 2.10 + 5 u
= 6 u + 2.10
6 u + 2.10 = 30.30
6 u = 30.30 - 2.10
6 u = 28.20
1 u = 28.20 ÷ 6 = 4.70
Cost of 1 marble
= 4.70 + 2.10
= $6.80
(b)
Cost of 5 marbles and 8 stickers
= 5 x 6.80 + 8 x 4.70
= 34.00 + 37.60
= $71.60
Answer(s): (a) $6.80; (b) $71.60