Final answer:
The schedule of reinforcement being used is a fixed ratio schedule, where a 5-minute break is allowed after every 10 math problems.
Step-by-step explanation:
The schedule of reinforcement being used in this scenario is a fixed ratio schedule. A fixed ratio schedule is when reinforcement is delivered after a set number of responses or behaviors occur. In this case, the student allows themselves a 5-minute break after completing every 10 math problems. The reinforcement (the break) occurs after a fixed ratio (10 math problems).