Adam pays $15.70 for 1 marble and 5 stickers.
The marble costs $1.30 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 5 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 + 1.30
Cost of 5 stickers
= 5 x 1 u
= 5 u
Total cost of 1 marble and 5 stickers
= 1 u + 1.30 + 5 u
= 6 u + 1.30
6 u + 1.30 = 15.70
6 u = 15.70 - 1.30
6 u = 14.40
1 u = 14.40 ÷ 6 = 2.40
Cost of 1 marble
= 2.40 + 1.30
= $3.70
(b)
Cost of 5 marbles and 8 stickers
= 5 x 3.70 + 8 x 2.40
= 18.50 + 19.20
= $37.70
Answer(s): (a) $3.70; (b) $37.70