Uncle Zhang rides a bicycle to work, and travels 4 kilometers in (2/5) hours. How many kilometers per hour? What is the column or equation.
张叔叔骑自行车上班，(2/5)小时行4千米．每小时行多少千米？列式或方程是多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">4 / (2/5)</gadget>
<output>10</output>

<result>10</result>