30% of a number is 150, what is this number?
一个数的30%是150，这个数是多少．
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">150 / (3/10)</gadget>
<output>500</output>

<result>500</result>