Xiao Liang went to school from home. He walked 40 meters per minute. After walking for 2 minutes, he found that he would be 2 minutes late; he changed to a speed of 50 meters per minute and arrived at school 2 minutes earlier. The distance between Liang's home and school.
小亮从家去上学，他每分钟走40米，走了2分钟后，发现这样下去将要迟到2分钟；他改用每分钟50米的速度前进，结果到校时提前了2分钟，求小亮家到学校间的路程．
<gadget id="calculator">40 * 2</gadget>
<output>80</output>

<gadget id="calculator">50 * 2</gadget>
<output>100</output>

<gadget id="calculator">80 + 100</gadget>
<output>180</output>

<gadget id="calculator">50 - 40</gadget>
<output>10</output>

<gadget id="calculator">180 / 10</gadget>
<output>18</output>

<gadget id="calculator">18 - 5</gadget>
<output>13</output>

<gadget id="calculator">50 * 13</gadget>
<output>650</output>

<gadget id="calculator">650 + 100</gadget>
<output>750</output>

<result>750</result>