Adam spends $16.30 on 3 marbles and 4 beads.
A marble costs $1.70 more than 1 bead.
- How much does 1 marble cost?
- How much do 6 marbles cost?
- How much do a bead and 6 marbles cost?
- How much do 6 marbles cost more than 1 bead?
(a)
Let the cheaper item be 1 u.
Cost of 1 bead = 1 u
Cost of 1 marble = 1 u + 1.70
Total cost of 3 marbles and 4 beads
= 3(1 u + 1.70) + 4 u
= 3 u + 5.10 + 4 u
= 3 u + 4 u + 5.10
= 7 u + 5.10
7 u + 5.10 = 16.30
7 u = 16.30 - 5.10
7 u = 11.20
1 u = 11.20 ÷ 7 = 1.60
Cost of 1 marble
= 1 u + 1.70
= 1.60 + 1.70
= $3.30
(b)
Cost of 6 marbles
= 6 x 3.30
= $19.80
(c)
Cost of 1 bead and 6 marbles
= 1.60 + 19.80
= $21.40
(d)
Cost of 6 marbles more than 1 bead
= 19.80 - 1.60
= $18.20
Answer(s): (a) $3.30; (b) $19.80; (c) $21.40; (d) $18.20