4 stickers and 1 bead cost $23.10.
1 sticker and 4 beads cost $23.40.

1. Find the cost of 1 sticker and 1 bead.
2. Find the cost of 1 bead.
3. Find the cost of 1 sticker.
4. Find the cost of 7 stickers and 7 beads.

(a)
4 stickers + 1 bead = 23.10 --- (1)
1 sticker + 4 beads = 23.40 --- (2)

(1) + (2)
5 stickers + 5 beads = 23.10 + 23.40
5 stickers + 5 beads = 46.50 --- (3)

(3) _{÷ 5}
5 stickers + 5 beads = 46.50
1 sticker + 1 bead = 46.50 ÷ 5
1 sticker + 1 bead = 9.30 --- (4)

(b)
(2) - (4)
(1 sticker + 4 beads) - (1 sticker + 1 marble) = 23.40 - 9.30
1 sticker - 1 sticker + 4 beads - 1 bead = 14.10
3 beads = 14.10
1 bead = 14.10 ÷ 3 = 4.70

Cost of 1 bead = $4.70

(c)
Substitute 1 bead = 4.70 into (4).
1 sticker + 1 bead = 9.30
1 sticker + 4.70 = 9.30
1 sticker = 9.30 - 4.70 = 4.60

Cost of 1 sticker = $4.60

(d)
(4) _{x 7}
1 sticker + 1 bead = 9.30
7 x (1 sticker + 1 marble) = 7 x 9.30
7 stickers + 7 beads = 65.10

Cost of 7 stickers and 7 beads = $65.10

Answer(s): (a) $9.30; (b) $4.70; (c) $4.60; (d) $65.10