Steve and Melanie have jobs folding shirts at a store. Every day, they each have 100 shirts to fold. When they finish folding, they can leave. On the first day of the job, Melanie finishes folding in one and a half hours (90 minutes) and leaves, but Steve still has 10 shirts left. The next day, Steve decides to be crafty. When Melanie’s not looking, he moves 5 shirts from his pile to her pile. This means that Melanie will be folding 105 shirts, and Steve 95 shirts. Steve believes he’ll finish at the same time as Melanie, but is surprised when she once again finishes before him.
Assuming that both Steve and Melanie’s folding speeds never change, why was Steve wrong about his prediction?