Problem 42901. Free-time Equation

Given a 7-day week, an nc -number of tc -hour classes, ta -hours awake in a day, and tw -hours that you work in a week....

Write an equation that will calculate the amount of free-time you have in a typical week.

NOTE: Read the top sentence for a better understanding of what each variable means, and assume that a tc -hour class will only take tc -hours from your week...