Final answer:
In order for a cosmetology student to work on patrons, they must complete a certain number of training hours.
Step-by-step explanation:
In order to work on patrons, a cosmetology student typically needs to complete a certain number of hours of training. The specific number of hours required can vary depending on the state and the licensing requirements set by the cosmetology board. As an example, let's say that in a particular state, a cosmetology student is required to complete 1,200 hours of training before they can work on patrons.
To calculate how many hours a cosmetology student shall have before they can work on patrons, you would subtract the hours already completed by the student from the total required hours. So if the student has completed 800 hours of training, they would still need to complete 400 more hours before they can work on patrons.