Adam spends $15.10 on 2 marbles and 3 stickers.
A marble costs $1.30 more than 1 sticker.
- How much does 1 marble cost?
- How much do 6 marbles cost?
- How much do a sticker and 6 marbles cost?
- How much do 6 marbles cost more than 1 sticker?
(a)
Let the cheaper item be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.30
Total cost of 2 marbles and 3 stickers
= 2(1 u + 1.30) + 3 u
= 2 u + 2.60 + 3 u
= 2 u + 3 u + 2.60
= 5 u + 2.60
5 u + 2.60 = 15.10
5 u = 15.10 - 2.60
5 u = 12.50
1 u = 12.50 ÷ 5 = 2.50
Cost of 1 marble
= 1 u + 1.30
= 2.50 + 1.30
= $3.80
(b)
Cost of 6 marbles
= 6 x 3.80
= $22.80
(c)
Cost of 1 sticker and 6 marbles
= 2.50 + 22.80
= $25.30
(d)
Cost of 6 marbles more than 1 sticker
= 22.80 - 2.50
= $20.30
Answer(s): (a) $3.80; (b) $22.80; (c) $25.30; (d) $20.30