On a certain day, the time ratio of day and night in Wuhan is 7:5, how many hours of night is there in Wuhan on this day?
某一天中，武汉白昼和黑夜的时间比是7：5，武汉这天的黑夜有多少小时．
<gadget id="calculator">7 + 5</gadget>
<output>12</output>

<gadget id="calculator">5 / 12</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">24 * (5/12)</gadget>
<output>10</output>

<result>10</result>