Adam pays $18.30 for a marble, a bead and a sticker.
The marble costs $2.80 less than the bead.
The bead costs $1.60 less than the sticker.
What is the cost of 5 stickers more than 2 marbles?
Choose the cheapest item to be 1 u.

Cost of the marble = 1 u
Cost of the bead = 1 u + 2.80
Cost of the sticker = 1 u + 2.80 + 1.60 = 1 u + 4.40

Total cost of the marble, the bead and the sticker
= 1 u + 1 u + 2.80 + 1 u + 4.40
= 3 u + 7.20

3 u + 7.20 = 18.30
3 u = 18.30 - 7.20
3 u = 11.10

1 u = 11.10 ÷ 3 = 3.70

Cost of 5 stickers more than 2 marbles
= 5 x (1 u + 4.40) - 2 x 1 u
= 5 u + 22.00 - 2 u
= 3 u + 22.00
= 3 x 3.70 + 22.00
= 11.10 + 22.00
= $33.10

Answer(s): $33.10