It is known that 2:5=6:15, if the 6 in the ratio is changed to 9, then how much should 15 be changed to.
已知2：5=6：15，如果将比例中的6改为9，那么15应改为多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">9 / (2/5)</gadget>
<output>45/2 = around 22.5</output>

<result>45/2 = around 22.5</result>