and B are traveling in opposite directions along the rail tracks. At this time, a train is coming towards A at a constant speed. The train passes by A in 15 seconds, and then passes by B in 17 seconds. seconds, it is known that the walking speed of both of them is 3.6 km/h, how long is this train?
甲、乙两人分别沿铁轨反向而行，此时，一列火车匀速地向甲迎面驶来，列车在甲身旁开过，用了15秒，然后在乙身旁开过，用了17秒，已知两人的步行速度都是3.6千米/小时，这列火车有多长？
<gadget id="calculator">15 + 17</gadget>
<output>32</output>

<gadget id="calculator">17 - 15</gadget>
<output>2</output>

<gadget id="calculator">32 / 2</gadget>
<output>16</output>

<gadget id="calculator">16 + 1</gadget>
<output>17</output>

<gadget id="calculator">15 * 17</gadget>
<output>255</output>

<result>255</result>