25% of a number is 12, what is 15% of this number?
一个数的25%是12，这个数的15%是多少．
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">12 / (1/4)</gadget>
<output>48</output>

<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">48 * (3/20)</gadget>
<output>36/5 = around 7.2</output>

<result>36/5 = around 7.2</result>