To build a road, build (2/5) kilometers every day. It is known that the full length (16/25) has been repaired in 4 days. How many kilometers is this road?
修一条路，每天修(2/5)千米，已知4天修了全长的(16/25)，这条路长多少千米？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">16 / 25</gadget>
<output>16/25 = around 0.64</output>

<gadget id="calculator">4 / (16/25)</gadget>
<output>25/4 = around 6.25</output>

<gadget id="calculator">(2/5) * (25/4)</gadget>
<output>5/2 = around 2.5</output>

<result>5/2 = around 2.5</result>