A sticker, a marble and a bead costs $9.30 altogether.
The sticker costs $3.20 less than the marble.
The bead costs $1.10 more than the marble.
How much do 2 beads cost?
Choose the cheapest item to be 1 u.
The sticker costs $3.20 less than the marble.
The cheapest item is the sticker.

Cost of the sticker = 1 u
Cost of the marble = 1 u + 3.20
Cost of the bead = 1 u + 3.20 + 1.10 = 1 u + 4.30

Total cost of the sticker, the marble and the bead
= 1 u + 1 u + 3.20 + 1 u + 4.30
= 1 u + 1 u + 1 u + 3.20 + 4.30
= 3 u + 7.5

3 u + 7.50 = 9.30
3 u = 9.30 - 7.50
3 u = 1.80

1 u = 1.80 ÷ 3 = 0.60

Cost of 2 beads
= 2 x (1 u + 4.30)
= 2 x (0.60 + 4.30)
= 2 x 4.90
= $9.80

Answer(s): $9.80