Adam pays $18.10 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 = 18.10
6 u = 18.10 - 1.90
6 u = 16.20
1 u = 16.20 ÷ 6 = 2.70
Cost of 1 marble
= 2.70 + 1.90
= $4.60
(b)
Cost of 5 marbles and 7 stickers
= 5 x 4.60 + 7 x 2.70
= 23.00 + 18.90
= $41.90
Answer(s): (a) $4.60; (b) $41.90