Zhang Ming and Hu Dong went from A to B at the same time. The speed ratio between Zhang Ming and Hu Dong was 5:4. When Zhang Ming walked 2/5 of the whole journey, Hu Dong walked 1.6 kilometers. A and B How many kilometers apart?
张明与胡东同时从甲地到乙地，张明与胡东的速度比5：4，当张明走了全程的(2/5)时，胡东走了1.6千米，甲、乙相距多少千米？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(2/5) * (4/5)</gadget>
<output>8/25 = around 0.32</output>

<gadget id="calculator">1.6 / (8/25)</gadget>
<output>5</output>

<result>5</result>