Adam pays $43.90 for 1 marble and 7 stickers.
The marble costs $1.50 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 3 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.50
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 1.50 + 7 u
= 8 u + 1.50
8 u + 1.50 = 43.90
8 u = 43.90 - 1.50
8 u = 42.40
1 u = 42.40 ÷ 8 = 5.30
Cost of 1 marble
= 5.30 + 1.50
= $6.80
(b)
Cost of 7 marbles and 3 stickers
= 7 x 6.80 + 3 x 5.30
= 47.60 + 15.90
= $63.50
Answer(s): (a) $6.80; (b) $63.50