Adam pays $39 for 3 stickers and 5 marbles.
10 stickers cost as much as 5 marbles.
- How much is 1 sticker?
- How much is 1 marble?
- How much is 4 marbles and 2 stickers?
(a)
Choose the smaller group to be 1 u.
Cost of 10 stickers = Cost of 5 marbles
Cost of 2 stickers = Cost of 1 marble
Cost of 1 sticker = 1 u
Cost of 1 marble = 2 u
Cost of 3 stickers
= 3 x 1 u
= 3 u
Cost of 5 marbles
= 5 x 2 u
= 10 u
Total cost of 3 stickers and 5 marbles
= 3 u + 10 u
= 13 u
13 u = 39
1 u = 39 ÷ 13 = 3
Cost of 1 sticker = 1 u = $3
(b)
Cost of 1 marble
= 2 u
= 2 x 3
= $6
(c)
Cost of 4 marbles and 2 stickers
= 4 x 2 u + 2 x 1 u
= 8 u + 2 u
= 10 u
= 10 x 3
= $30
Answer(s): (a) $3; (b) $6; (c) $30