The ratio of two numbers A and B is 3:5, A's number is 15, what is B's number.
甲、乙两个数的比是3：5，甲数是15，乙数是多少．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">15 / (3/5)</gadget>
<output>25</output>

<result>25</result>