If 40% of a certain number is 8, what is 25% of this number?
某数的40%是8，这个数的25%是多少．
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">8 / (2/5)</gadget>
<output>20</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">20 * (1/4)</gadget>
<output>5</output>

<result>5</result>