A boat travels 12.5 kilometers per hour and reaches its destination in 42 hours. How many hours will it take to drive 2.5 kilometers per hour?
一只船每小时行驶12.5千米，42小时到达目的地．如果每小时多行驶2.5千米，需要多少小时？
<gadget id="calculator">12.5 * 42</gadget>
<output>525</output>

<gadget id="calculator">12.5 + 2.5</gadget>
<output>15</output>

<gadget id="calculator">525 / 15</gadget>
<output>35</output>

<result>35</result>