A, B, and C are running a 100-meter race. When A reaches the finish line, B runs 80 meters; C runs 70 meters; when B reaches the finish line, how many meters is C away from the finish line?
甲乙丙三人进行百米赛跑．当甲到达终点时，乙跑了80米；丙跑了70米；当乙到达终点时，丙离终点还有多少米．
<gadget id="calculator">7 / 8</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">1 - (7/8)</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">100 * (1/8)</gadget>
<output>25/2 = around 12.5</output>

<result>25/2 = around 12.5</result>