Adam pays $16.70 for 1 marble and 5 stickers.
The marble costs $2.90 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 + 2.90
Cost of 5 stickers
= 5 x 1 u
= 5 u
Total cost of 1 marble and 5 stickers
= 1 u + 2.90 + 5 u
= 6 u + 2.90
6 u + 2.90 = 16.70
6 u = 16.70 - 2.90
6 u = 13.80
1 u = 13.80 ÷ 6 = 2.30
Cost of 1 marble
= 2.30 + 2.90
= $5.20
(b)
Cost of 5 marbles and 7 stickers
= 5 x 5.20 + 7 x 2.30
= 26.00 + 16.10
= $42.10
Answer(s): (a) $5.20; (b) $42.10