Adam pays $16.30 for 1 marble and 8 stickers.
The marble costs $2.80 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 marbles and 2 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.80
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 2.80 + 8 u
= 9 u + 2.80
9 u + 2.80 = 16.30
9 u = 16.30 - 2.80
9 u = 13.50
1 u = 13.50 ÷ 9 = 1.50
Cost of 1 marble
= 1.50 + 2.80
= $4.30
(b)
Cost of 8 marbles and 2 stickers
= 8 x 4.30 + 2 x 1.50
= 34.40 + 3.00
= $37.40
Answer(s): (a) $4.30; (b) $37.40