When the minute hand on the clock face rotates 180°, how much does the hour hand rotate correspondingly?
钟面上分针转动180°，时针相应的转动多少°．
<gadget id="calculator">180 / 30</gadget>
<output>6</output>

<gadget id="calculator">6 * 2.5</gadget>
<output>15</output>

<result>15</result>