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?
The total time of the programs is 6 programs * 30 minutes/program = <<6*30=180>>180 minutes
A quarter of this time is spent on commercials, so that's 180 minutes / 4 = <<180/4=45>>45 minutes
#### 45