The inner term 3 of the ratio 2:3=4:6 is increased by 9, how much should the outer term 6 be increased to make the ratio valid
比例2：3=4：6的内项3增加9，要使比例成立，外项6应增加多少
<gadget id="calculator">3 + 9</gadget>
<output>12</output>

<gadget id="calculator">12 * 4</gadget>
<output>48</output>

<gadget id="calculator">48 / 2</gadget>
<output>24</output>

<gadget id="calculator">24 - 6</gadget>
<output>18</output>

<result>18</result>