Adam pays $20 for 4 marbles and 3 beads.
4 marbles cost as much as 2 beads.
- How much is 1 marble?
- How much is 1 bead?
- How much is 2 beads and 3 marbles?
(a)
Choose the smaller group to be 1 u.
Cost of 4 marbles = Cost of 2 beads
Cost of 2 marbles = Cost of 1 bead
Cost of 1 marble = 1 u
Cost of 1 bead = 2 u
Cost of 4 marbles
= 4 x 1 u
= 4 u
Cost of 3 beads
= 3 x 2 u
= 6 u
Total cost of 4 marbles and 3 beads
= 4 u + 6 u
= 10 u
10 u = 20
1 u = 20 ÷ 10 = 2
Cost of 1 marble = 1 u = $2
(b)
Cost of 1 bead
= 2 u
= 2 x 2
= $4
(c)
Cost of 2 beads and 3 marbles
= 2 x 2 u + 3 x 1 u
= 4 u + 3 u
= 7 u
= 7 x 2
= $14
Answer(s): (a) $2; (b) $4; (c) $14