Adam pays $2.10 for a marble and a bead.
The marble costs 2 times as much as the bead.
- What is the cost of 1 marble?
- How much is the cost of 3 beads and 4 marbles?
(a)
Cost of a bead = 1 u
Cost of a marble = 2 u
Total cost of a bead and a marble
= 1 u + 2 u
= 3 u
3 u = 2.10
1 u = 2.10 ÷ 3 = 0.70
Cost of the marble
= 2 u
= 2 x 0.70
= $1.40
(b)
Cost of 3 beads and 4 marbles
= 3 x 1 u + 4 x 2 u
= 3 u + 8 u
= 11 u
= 11 x 0.70
= $7.70
Answer(s): (a) $1.40; (b) $7.70