Adam pays $30 for 3 marbles and 4 beads.
3 marbles cost as much as 1 bead.
- How much is 1 marble?
- How much is 1 bead?
- How much is 3 beads and 5 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 bead = 3 u
Cost of 3 marbles
= 3 x 1 u
= 3 u
Cost of 4 beads
= 4 x 3 u
= 12 u
Total cost of 3 marbles and 4 beads
= 3 u + 12 u
= 15 u
15 u = 30
1 u = 30 ÷ 15 = 2
Cost of 1 marble
= 1 u
= $2
(b)
Cost of 1 bead
= 3 u
= 3 x 2
= $6
(c)
Cost of 3 beads and 5 marbles
= 3 x 3 u + 5 x 1 u
= 9 u + 5 u
= 14 u
= 14 x 2
= $28
Answer(s): (a) $2; (b) $6; (c) $28
