Adam pays $25.70 for a marble, a bead and a sticker.
The marble costs $3.50 less than the bead.
The bead costs $1.60 less than the sticker.
What is the cost of 6 stickers more than 5 marbles?
Choose the cheapest item to be 1 u.

Cost of the marble = 1 u
Cost of the bead = 1 u + 3.50
Cost of the sticker = 1 u + 3.50 + 1.60 = 1 u + 5.10

Total cost of the marble, the bead and the sticker
= 1 u + 1 u + 3.50 + 1 u + 5.10
= 3 u + 8.60

3 u + 8.60 = 25.70
3 u = 25.70 - 8.60
3 u = 17.10

1 u = 17.10 ÷ 3 = 5.70

Cost of 6 stickers more than 5 marbles
= 6 x (1 u + 5.10) - 5 x 1 u
= 6 u + 30.60 - 5 u
= 1 u + 30.60
= 1 x 5.70 + 30.60
= 5.70 + 30.60
= $36.30

Answer(s): $36.30