Adam pays $27.70 for 1 marble and 5 stickers.
The marble costs $1.90 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 5 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 + 1.90
Cost of 5 stickers
= 5 x 1 u
= 5 u
Total cost of 1 marble and 5 stickers
= 1 u + 1.90 + 5 u
= 6 u + 1.90
6 u + 1.90 = 27.70
6 u = 27.70 - 1.90
6 u = 25.80
1 u = 25.80 ÷ 6 = 4.30
Cost of 1 marble
= 4.30 + 1.90
= $6.20
(b)
Cost of 5 marbles and 7 stickers
= 5 x 6.20 + 7 x 4.30
= 31.00 + 30.10
= $61.10
Answer(s): (a) $6.20; (b) $61.10