Adam pays $40.10 for 1 marble and 7 stickers.
The marble costs $1.70 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 6 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.70
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 1.70 + 7 u
= 8 u + 1.70
8 u + 1.70 = 40.10
8 u = 40.10 - 1.70
8 u = 38.40
1 u = 38.40 ÷ 8 = 4.80
Cost of 1 marble
= 4.80 + 1.70
= $6.50
(b)
Cost of 7 marbles and 6 stickers
= 7 x 6.50 + 6 x 4.80
= 45.50 + 28.80
= $74.30
Answer(s): (a) $6.50; (b) $74.30