Adam buys a bead for $6.
He also buys a marble.
The bead costs 3 times as much as the marble.
- How much less does the marble cost than the bead?
- How much does he spend altogether?
- How much are 2 marbles?
- What is the difference in cost between 3 beads and 3 marbles?
(a)
Choose the cheaper item to be 1 u.
The bead costs 3 times as much as the marble.
The marble is cheaper.
Cost of the marble = 1 u
Cost of the bead = 3 u = $6
3 u = 6
1 u = 6 ÷ 3 = 2
Amount that the marble costs less than the bead
= 3 u - 1 u
= 2 u
= 2 x 2
= $4
(b)
Total amount that Adam spends
= 1 u + 3 u
= 4 u
= 4 x 2
= $8
(c)
Cost of 2 marbles
= 2 x 1 u
= 2 u
= 2 x 2
= $4
(d )
Difference in the cost between 4 beads and 3 marbles
= (3 x 3 u) - (3 x 1 u)
= 9 u - 3 u
= 6 u
= 6 x 2
= $12
Answer(s): (a) $4; (b) $8; (c) $4; (d) $12