When the clock showed 2:30, Xiao Ming started to do his summer homework. When he finished his homework, he found that the angle of the hour hand was exactly 15°. How many minutes did he spend doing his homework?
当钟面显示2时30分的时候，小明开始做暑假作业，当他做完作业时发现时针转过的角度正好是15°，他做作业花了多少分钟．
<gadget id="calculator">360 / 60</gadget>
<output>6</output>

<gadget id="calculator">5 / 60</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">6 * (1/12)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">15 / (1/2)</gadget>
<output>30</output>

<result>30</result>