Adam pays $19.90 for 1 marble and 6 stickers.
The marble costs $2.40 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 + 2.40
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 2.40 + 6 u
= 7 u + 2.40
7 u + 2.40 = 19.90
7 u = 19.90 - 2.40
7 u = 17.50
1 u = 17.50 ÷ 7 = 2.50
Cost of 1 marble
= 2.50 + 2.40
= $4.90
(b)
Cost of 6 marbles and 4 stickers
= 6 x 4.90 + 4 x 2.50
= 29.40 + 10.00
= $39.40
Answer(s): (a) $4.90; (b) $39.40