A ship departs from Port A at 7:30 am and arrives at Port B at 2:30 pm, traveling an average of 30 kilometers per hour. How many kilometers is the waterway between these two ports?
一艘轮船上午7时30分从甲港出发，下午2时30分到达乙港，平均每小时行30千米．这两个港口之间的水路长多少千米？
<gadget id="calculator">30 * 7</gadget>
<output>210</output>

<result>210</result>