40% of a number is 20, what is 75% of this number?
一个数的40%是20，这个数的75%是多少．
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">20 / (2/5)</gadget>
<output>50</output>

<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">50 * (3/4)</gadget>
<output>75/2 = around 37.5</output>

<result>75/2 = around 37.5</result>