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 once 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

Lisa spends a total of 4 + 4 = <<4+4=8>>8 hours in class each week.
She has 168 – 8 – 8 – 21 = <<168-8-8-21=131>>131 hours left.
She needs 8 * 7 = <<8*7=56>>56 hours of sleep each week.
She can spend 131 – 56 = <<131-56=75>>75 hours on work. Answer: \boxed{75}.