Adam pays $2.80 for a marble and a bead.
The marble costs 3 times as much as the bead.
- What is the cost of 1 marble?
- How much is the cost of 2 beads and 5 marbles?
(a)
Cost of a bead = 1 u
Cost of a marble = 3 u
Total cost of a bead and a marble
= 1 u + 3 u
= 4 u
4 u = 2.80
1 u = 2.80 ÷ 4 = 0.70
Cost of the marble
= 3 u
= 3 x 0.70
= $2.10
(b)
Cost of 2 beads and 5 marbles
= 2 x 1 u + 5 x 3 u
= 2 u + 15 u
= 17 u
= 17 x 0.70
= $11.90
Answer(s): (a) $2.10; (b) $11.90