Well lets take this step by step:
24 minutes tv - 6 minutes commercial = 18 minutes of tv
1 hour = 60 min
60 + 36 = 96
96/24 = 4 so that means 24 + 24 + 24 + 24 = 96
so all you do now is this:
since 24 - 6 is 18 multiply 18 by 4 to get 72
so the answer is 72 minutes of tv