Step-by-step explanation
The ways a waiter and a dishwasher are paid are different. A waiter has a flat $25 dollars daily wage so despite having a lower payment per hour than a dishwasher is logical and expected that a waiter earns more money in the short run. However, as working hours increase the inportance of that fixed daily payment decreases and the contribution to the total payment given by the payment per hour begins to dominate.
It's easy to see this in the graph of both wages. Both are straight lines but the one representing a waiter's wage starts with an offset whereas that of a dishwasher starts at 0. However, since the later receives a better hourly payment the slope of its graph is higher and at some point it surpasses the wage of the waiter. This also happens at a reasonable number of hours (7 hours) because the difference between payments per hour (which define the slopes of the lines) is not minimal.