Adam spends $14.70 on 2 marbles and 3 stickers.
A marble costs 2 times as much as 1 sticker.
- How much does 1 marble cost?
- How much do 3 marbles cost?
- How much do a sticker and 3 marbles cost?
- How much does 1 sticker cost less than 3 marbles?
(a)
Let the cheaper item be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 2 u
Cost of 2 marbles = 2 x 2 u = 4 u
Cost of 3 stickers = 3 x 1 u = 3 u
Total cost of 2 marbles and 3 stickers
= 4 u + 3 u
= 7 u
7 u = 14.70
1 u = 14.70 ÷ 7 = 2.10
Cost of 1 marble
= 2 u
= 2 x 2.10
= $4.20
(b)
Cost of 3 marbles
= 3 x 4.20
= $12.60
(c)
Cost of 1 sticker and 3 marbles
= 2.10 + 12.60
= $14.70
(d)
Cost of 1 sticker less than 3 marbles
= 12.60 - 2.10
= $10.50
Answer(s): (a) $4.20; (b) $12.60; (c) $14.70; (d) $10.50