One-fourth of the airing time of a television program is spent on commercials. If there are 6 thirty-minute programs, how many minutes are spent on commercials for the whole duration of the 6 programs? Let's think first. Chain of thought:
The total time of the programs is 6 programs * 30 minutes / program = 180 minutes. A quarter of this time is spent on commercials, so that's 180 minutes / 4 = 45 minutes.
Therefore, the answer is 45.