A:B=5:9, if A increases by 15, how much should B be increased to keep the ratio constant.
A：B=5：9，如果A增加15，要使比值不变，B应该增加多少．
<gadget id="calculator">15 / 5</gadget>
<output>3</output>

<gadget id="calculator">3 * 9</gadget>
<output>27</output>

<result>27</result>