Adam pays $21 for 3 marbles and 2 stickers.
2 marbles cost as much as 1 sticker.
- How much is 1 marble?
- How much is 1 sticker?
- How much is 2 stickers and 5 marbles?
(a)
Choose the smaller group to be 1 u.
Cost of 1 marble = 1 u
Cost of 2 marbles = 2 u
Cost of 1 sticker = 2 u
Cost of 3 marbles
= 3 x 1 u
= 3 u
Cost of 2 stickers
= 2 x 2 u
= 4 u
Total cost of 3 marbles and 2 stickers
= 3 u + 4 u
= 7 u
7 u = 21
1 u = 21 ÷ 7 = 3
Cost of 1 marble
= 1 u
= $3
(b)
Cost of 1 sticker
= 2 u
= 2 x 3
= $6
(c)
Cost of 2 stickers and 5 marbles
= 2 x 2 u + 5 x 1 u
= 4 u + 5 u
= 9 u
= 9 x 3
= $27
Answer(s): (a) $3; (b) $6; (c) $27