Adam pays $19.40 for 1 marble and 8 stickers.
The marble costs $2.30 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 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 + 2.30
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 2.30 + 8 u
= 9 u + 2.30
9 u + 2.30 = 19.40
9 u = 19.40 - 2.30
9 u = 17.10
1 u = 17.10 ÷ 9 = 1.90
Cost of 1 marble
= 1.90 + 2.30
= $4.20
(b)
Cost of 8 marbles and 4 stickers
= 8 x 4.20 + 4 x 1.90
= 33.60 + 7.60
= $41.20
Answer(s): (a) $4.20; (b) $41.20