Adam pays $37.70 for 1 marble and 6 stickers.
The marble costs $1.30 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 6 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 + 1.30
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 1.30 + 6 u
= 7 u + 1.30
7 u + 1.30 = 37.70
7 u = 37.70 - 1.30
7 u = 36.40
1 u = 36.40 ÷ 7 = 5.20
Cost of 1 marble
= 5.20 + 1.30
= $6.50
(b)
Cost of 6 marbles and 3 stickers
= 6 x 6.50 + 3 x 5.20
= 39.00 + 15.60
= $54.60
Answer(s): (a) $6.50; (b) $54.60