2 stickers and 1 bead cost $10.50.
1 sticker and 2 beads cost $7.20.
- Find the cost of 1 sticker and 1 bead.
- Find the cost of 1 bead.
- Find the cost of 1 sticker.
- Find the cost of 9 stickers and 9 beads.
(a)
2 stickers + 1 bead = 10.50 --- (1)
1 sticker + 2 beads = 7.20 --- (2)
(1) + (2)
3 stickers + 3 beads = 10.50 + 7.20
3 stickers + 3 beads = 17.70 --- (3)
(3)
÷ 3
3 stickers + 3 beads = 17.70
1 sticker + 1 bead = 17.70 ÷ 3
1 sticker + 1 bead = 5.90 --- (4)
Cost of 1 sticker and 1 bead = $5.90
(b)
(2) - (4)
(1 sticker + 2 beads) - (1 sticker + 1 marble) = 7.20 - 5.90
1 sticker - 1 sticker + 2 beads - 1 bead = 1.30
1 bead = 1.30
Cost of 1 bead = $1.30
(c)
Substitute 1 bead = 1.30 into (4).
1 sticker + 1 bead = 5.90
1 sticker + 1.30 = 5.90
1 sticker = 5.90 - 1.30 = 4.60
Cost of 1 sticker = $4.60
(d)
(4)
x 9 1 sticker + 1 bead = 5.90
9 x (1 sticker + 1 marble) = 9 x 5.90
9 stickers + 9 beads = 53.10
Cost of 9 stickers and 9 beads = $53.10
Answer(s): (a) $5.90; (b) $1.30; (c) $4.60; (d) $53.10