Adam pays $34.90 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 7 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 = 34.90
7 u = 34.90 - 1.30
7 u = 33.60
1 u = 33.60 ÷ 7 = 4.80
Cost of 1 marble
= 4.80 + 1.30
= $6.10
(b)
Cost of 6 marbles and 7 stickers
= 6 x 6.10 + 7 x 4.80
= 36.60 + 33.60
= $70.20
Answer(s): (a) $6.10; (b) $70.20