Adam pays $35.50 for 1 marble and 7 stickers.
The marble costs $2.70 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 8 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.70
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 2.70 + 7 u
= 8 u + 2.70
8 u + 2.70 = 35.50
8 u = 35.50 - 2.70
8 u = 32.80
1 u = 32.80 ÷ 8 = 4.10
Cost of 1 marble
= 4.10 + 2.70
= $6.80
(b)
Cost of 7 marbles and 8 stickers
= 7 x 6.80 + 8 x 4.10
= 47.60 + 32.80
= $80.40
Answer(s): (a) $6.80; (b) $80.40