A and B travel from point a to point b at the same time at constant speeds. When A has traveled 40% of the whole journey, B has traveled 9.6 kilometers; when A reaches point b, B is still (1/5) away from point b. Find the distance between places a and b.
甲、乙两人各自以不变的速度，同时从a地到b地．当甲行了全程的40%时，乙行了9.6千米；当甲到达b地时，乙距b地还差(1/5)的路程．求a、b两地的距离．
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / (2/5)</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">9.6 / (4/5)</gadget>
<output>12</output>

<gadget id="calculator">(5/2) * 12</gadget>
<output>30</output>

<result>30</result>