A and B practice running. If A asks B to run 10 meters first, then A can catch up with B in 5 seconds; if let B run for 2 seconds first, then A can catch up with B in 4 seconds. Seek the speed of armor.
甲、乙两人练习跑步，如果甲让乙先跑10米，那么甲跑5秒钟可追上乙；如果让乙先跑2秒钟，那么甲跑4秒钟可追上乙．求甲的速度．
<gadget id="calculator">10 / 5</gadget>
<output>2</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 + 2</gadget>
<output>6</output>

<result>6</result>