Let:
x = Cost of each ride
y = Cost of each drink
z = Cost of each bag of pocorn
so:
Henry rode on 5 rides, bought 2 drinks , 1 bag of popcorn and spent $20.50:

Mary spent $16.50 on 3 rides, 3 drinks and 1 bag of popcorn:

Tim rode rode on 6 rides only purchased 1 drink and spent $20.00:

Solve the system:


Answer:
Each ride cost $3