A train travels a total of 1504 kilometers in 32 hours. It is known that the train first runs at a speed of 50 kilometers per hour for 11 hours, and then at a speed of 42 kilometers per hour for 9 hours. Find the average speed during the rest of the time.
一列火车32小时共行1504千米．已知这列火车先以每小时50千米的速度行驶11小时，又以每小时42千米的速度行驶9小时，求在其余时间内的平均速度．
<gadget id="calculator">50 * 11</gadget>
<output>550</output>

<gadget id="calculator">42 * 9</gadget>
<output>378</output>

<gadget id="calculator">550 + 378</gadget>
<output>928</output>

<gadget id="calculator">1_504 - 928</gadget>
<output>576</output>

<gadget id="calculator">32 - 11 - 9</gadget>
<output>12</output>

<gadget id="calculator">576 / 12</gadget>
<output>48</output>

<result>48</result>