The ratio of A and B is 13:8, multiply A by 3, how much must be added to B to keep the ratio unchanged?
甲、乙两数的比为13：8，甲数乘3，乙数要加上几，比值才能不变？
<gadget id="calculator">24 - 8</gadget>
<output>16</output>

<result>16</result>