Adam buys a marble for $3.
He also buys a bead.
The bead costs 3 times as much as the marble.
- How much less does the bead cost than the marble?
- How much does he spend altogether?
- How much are 3 beads?
- How much are 5 beads and 2 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 = $3
Cost of the bead = 3 u
Amount that the marble costs less than the bead
= 3 u - 1 u
= 2 u
= 2 x 3
= $6
(b)
Total amount that Adam spends
= 1 u + 3 u
= 4 u
= 4 x 3
= $12
(c)
Cost of 3 beads
= 3 x 3 u
= 9 u
= 9 x 3
= $27
(d )
Cost of 5 beads and 2 marbles
= 5 x 3 u + 2 x 1 u
= 15 u + 2 u
= 17 u
= 17 x 3
= $51
Answer(s): (a) $6; (b) $12; (c) $27; (d) $51