Adam pays $11.10 for 3 stickers and 2 beads.
A sticker costs $2.20 more than 1 bead.
What is the cost of 2 stickers and 4 beads?
Choose the cheaper item to be 1 u.
1 sticker costs $2.20 more than 1 bead.
The cheaper item is the bead.

Cost of the bead = 1 u
Cost of the sticker = 1 u + 2.20

Cost of 3 stickers = 3 x (1 u + 2.20) = 3 u + 6.60
Cost of 2 beads = 2 u

Total cost of 3 stickers and 2 beads
= 3 u + 6.60 + 2 u
= 3 u + 2 u + 6.60
= 5 u + 6.60

5 u + 6.60 = 11.10
5 u = 11.10 - 6.60
5 u = 4.50

1 u = 4.50 ÷ 5 = 0.90

Cost of 2 stickers and 4 beads
= 2 x (1 u + 2.20) + 4 u
= 2 u + 4.40 + 4 u
= 2 u + 4 u + 4.40
= 6 u + 4.40
= 6 x 0.90 + 4.40
= 5.40 + 4.40
= $9.80

Answer(s): $9.80