Adam pays $33.40 for 1 marble and 6 stickers.
The marble costs $1.90 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 6 marbles and 5 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.90
Cost of 6 stickers
= 6 x 1 u
= 6 u
Total cost of 1 marble and 6 stickers
= 1 u + 1.90 + 6 u
= 7 u + 1.90
7 u + 1.90 = 33.40
7 u = 33.40 - 1.90
7 u = 31.50
1 u = 31.50 ÷ 7 = 4.50
Cost of 1 marble
= 4.50 + 1.90
= $6.40
(b)
Cost of 6 marbles and 5 stickers
= 6 x 6.40 + 5 x 4.50
= 38.40 + 22.50
= $60.90
Answer(s): (a) $6.40; (b) $60.90