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 = 
<gadget id="calculator">6*30</gadget>
<output>180</output>
180 minutes.
A quarter of this time is spent on commercials, so that's 180 minutes / 4 = 
<gadget id="calculator">180/4</gadget>
<output>45</output>
45 minutes.

<result>45</result>