Two people, A and B, are running a 100-meter race. When A reaches the finish line, B is still 20 meters away. Now the two run again, and the speed is the same as before. If they want to reach the finish line at the same time, how many meters should A's starting line be moved back?
甲、乙两人进行100米赛跑，当甲跑到终点时，乙还差20米．现在两人重新跑，而且速度和原来一样，要使两人同时到达终点，那么甲的起跑线应往后退多少米．
<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">100 * (5/4)</gadget>
<output>125</output>

<gadget id="calculator">125 - 100</gadget>
<output>25</output>

<result>25</result>