A train travels a total of 2481 kilometers in 32 hours. It is known that the train first travels at a speed of 75 kilometers per hour for 11 hours, and then travels at a speed of 80 kilometers for 9 hours. Find the speed of the rest of the time.
一列火车32小时共行驶2481千米，已知这列火车先以每小时75千米的速度行驶了11小时，又以80千米的速度行驶了9小时，求其余时间的行驶速度．
<gadget id="calculator">75 * 11</gadget>
<output>825</output>

<gadget id="calculator">80 * 9</gadget>
<output>720</output>

<gadget id="calculator">825 + 720</gadget>
<output>1_545</output>

<gadget id="calculator">2_481 - 1_545</gadget>
<output>936</output>

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

<gadget id="calculator">936 / 12</gadget>
<output>78</output>

<result>78</result>