Zhang Xiaodong left home to go to school in the county. After he walked at a speed of 50 meters per minute for 2 minutes, he realized that he might be 8 minutes late, so he speeded up and walked an extra 10 meters per minute. When he arrived at the school, he was still halfway to class. 5 minutes. How far is Zhang Xiaodong's home from the school?
张小冬离家到县城去上学，他以每分钟50米的速度走了2分钟后，发觉可能要迟到8分钟，于是他加快速度，每分钟多走10米，结果到学校时离上课还有5分钟．张小冬家离学校有多远？
<gadget id="calculator">50 * 8</gadget>
<output>400</output>

<gadget id="calculator">60 * 5</gadget>
<output>300</output>

<gadget id="calculator">400 + 300</gadget>
<output>700</output>

<gadget id="calculator">700 / 10</gadget>
<output>70</output>

<gadget id="calculator">70 + 8</gadget>
<output>78</output>

<gadget id="calculator">50 * 78</gadget>
<output>3_900</output>

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

<gadget id="calculator">3_900 + 100</gadget>
<output>4_000</output>

<result>4_000</result>