Adam pays $16.80 for 1 marble and 6 stickers.
The marble costs $2.10 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 6 marbles and 4 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 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 2.10 + 6 u
= 7 u + 2.10
7 u + 2.10 = 16.80
7 u = 16.80 - 2.10
7 u = 14.70
1 u = 14.70 ÷ 7 = 2.10
Cost of 1 marble
= 2.10 + 2.10
= $4.20
(b)
Cost of 6 marbles and 4 stickers
= 6 x 4.20 + 4 x 2.10
= 25.20 + 8.40
= $33.60
Answer(s): (a) $4.20; (b) $33.60