It takes 20 seconds for a train to pass through a 265-meter bridge, and 15 seconds to pass through a 190-meter cave at the same speed. Find the speed of the train in meters per second.
一列火车通过265米的桥需20秒钟，以同样的速度穿过190米的山洞需15秒钟．求这列火车的速度是多少米/秒．
<gadget id="calculator">265 - 190</gadget>
<output>75</output>

<gadget id="calculator">20 - 15</gadget>
<output>5</output>

<gadget id="calculator">75 / 5</gadget>
<output>15</output>

<result>15</result>