Charlie pays $16 for a bead and a marble.
The marble costs thrice as much as the bead.
- Find the cost of the bead.
- Find the cost of the marble.
- Find the difference in the cost of the marble and the bead.
(a)
Choose the cheaper item to be 1 u.
The marble costs thrice as much as the bead.
The bead is cheaper.
Cost of the bead = 1 u
Cost of the marble = 3 u
Total cost = 1 u + 3 u = 4 u
4 u = 16
1 u = 16 ÷ 4 = 4
Cost of the bead
= 1 u
= $4
(b)
Cost of the marble
= 3 u
= 3 x 4
= $12
(c)
Difference in the cost of the marble and the bead
= 3 u - 1 u
= 2 u
= 2 x 4
= $8
Answer(s): (a) $4; (b) $12; (c) $8