Final answer:
Mike is using a fixed ratio reinforcement schedule since he takes a break after a set number of pages read, which is predictable and does not vary.
Step-by-step explanation:
The schedule of reinforcement that Mike is using is a fixed ratio reinforcement schedule. This schedule is based on the number of responses between reinforcements. In Mike's case, he reads a set number of pages, which is five, before he takes a break. This number does not change and is based on his responses (reading pages). After every five pages, he gets the reinforcement, which is the break. This is predictable, as the reinforcement (break) occurs after a fixed number of responses (five pages).