Final answer:
To find the difference in cost per hour to rent skates at two rinks, subtract the hourly rate of one rink from the hourly rate of the other rink.
Step-by-step explanation:
To determine how many more dollars it costs per hour to rent skates at rink B than at rink A, we need to compare the hourly rates at both rinks. Let's say the hourly rate at rink A is $x and the hourly rate at rink B is $y. The difference in cost per hour is given by the equation y - x. Therefore, it costs y - x dollars per hour more to rent skates at rink B than at rink A.