Adam pays $18 for 3 marbles and 2 beads.
3 marbles cost as much as 1 bead.
- How much is 1 marble?
- How much is 1 bead?
- How much is 5 beads and 3 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 2 beads
= 2 x 3 u
= 6 u
Total cost of 3 marbles and 2 beads
= 3 u + 6 u
= 9 u
9 u = 18
1 u = 18 ÷ 9 = 2
Cost of 1 marble
= 1 u
= $2
(b)
Cost of 1 bead
= 3 u
= 3 x 2
= $6
(c)
Cost of 5 beads and 3 marbles
= 5 x 3 u + 3 x 1 u
= 15 u + 3 u
= 18 u
= 18 x 2
= $36
Answer(s): (a) $2; (b) $6; (c) $36
