Adam pays $39 for 4 marbles and 3 stickers.
3 marbles cost as much as 1 sticker.
- How much is 1 marble?
- How much is 1 sticker?
- How much is 3 stickers and 4 marbles?
(a)
Choose the smaller group to be 1 u.
Cost of 1 marble = 1 u
Cost of 3 marbles = 3 u
Cost of 1 sticker = 3 u
Cost of 4 marbles
= 4 x 1 u
= 4 u
Cost of 3 stickers
= 3 x 3 u
= 9 u
Total cost of 4 marbles and 3 stickers
= 4 u + 9 u
= 13 u
13 u = 39
1 u = 39 ÷ 13 = 3
Cost of 1 marble
= 1 u
= $3
(b)
Cost of 1 sticker
= 3 u
= 3 x 3
= $9
(c)
Cost of 3 stickers and 4 marbles
= 3 x 3 u + 4 x 1 u
= 9 u + 4 u
= 13 u
= 13 x 3
= $39
Answer(s): (a) $3; (b) $9; (c) $39