3 beads and 1 sticker cost $16.70.
1 bead and 3 stickers cost $14.10.

1. Find the cost of 1 bead and 1 sticker.
2. Find the cost of 1 sticker.
3. Find the cost of 1 bead.
4. Find the cost of 8 beads and 8 stickers.

(a)
3 beads + 1 sticker = 16.70 --- (1)
1 bead + 3 stickers = 14.10 --- (2)

(1) + (2)
4 beads + 4 stickers = 16.70 + 14.10
4 beads + 4 stickers = 30.80 --- (3)

(3) _{÷ 4}
4 beads + 4 stickers = 30.80
1 bead + 1 sticker = 30.80 ÷ 4
1 bead + 1 sticker = 7.70 --- (4)

(b)
(2) - (4)
(1 bead + 3 stickers) - (1 bead + 1 marble) = 14.10 - 7.70
1 bead - 1 bead + 3 stickers - 1 sticker = 6.40
2 stickers = 6.40
1 sticker = 6.40 ÷ 2 = 3.20

Cost of 1 sticker = $3.20

(c)
Substitute 1 sticker = 3.20 into (4).
1 bead + 1 sticker = 7.70
1 bead + 3.20 = 7.70
1 bead = 7.70 - 3.20 = 4.50

Cost of 1 bead = $4.50

(d)
(4) _{x 8}
1 bead + 1 sticker = 7.70
8 x (1 bead + 1 marble) = 8 x 7.70
8 beads + 8 stickers = 61.60

Cost of 8 beads and 8 stickers = $61.60

Answer(s): (a) $7.70; (b) $3.20; (c) $4.50; (d) $61.60