Lisa is taking two classes at a local community college. She sets aside 21 hours for homework a week with these two classes. The two classes are 4 hours each twice a week on Tuesday and Thursday. She wants to get a part-time job and ensure 8 hours of sleep each night. There are 168 hours in one week. How many hours can she work at most each week? Write and solve an inequality to determine the maximum amount of time she can work each week.

Answer 1

The two classes meet 4 hours per session, twice a week, for a total of 4 * 2 = <<4*2=8>>8 hours per week.
She spends 8 hours a week on each class, so a total of 8 + 8 = <<8+8=16>>16 hours per week.
She sets aside 21 hours for homework, so she has 168 - 21 = <<168-21=147>>147 hours left.
She wants 8 hours of sleep each night, so she sleeps 8 * 7 = <<8*7=56>>56 hours per week.
She spends 56 hours sleeping and 16 hours on class and homework, so she has 147 - 56 - 16 = <<147-56-16=75>>75 hours left.
Therefore, the maximum number of hours she can work each week is 75 hours. Answer: \boxed{75}.