In the ratio 3:4=9:12, if 8 is added to the latter term of the first ratio, how much should be added to the latter term of the second ratio to make the ratio still valid
在比例3：4=9：12中，若第一个比的后项加上8，要使比例仍然成立，则第二个比的后项应加上多少
<gadget id="calculator">12 * 9</gadget>
<output>108</output>

<gadget id="calculator">108 / 3</gadget>
<output>36</output>

<gadget id="calculator">36 - 12</gadget>
<output>24</output>

<result>24</result>