The ratio of two numbers A and B is 5:9, A's number is 10, what is B's number?
甲、乙两个数的比是5：9，甲数是10，乙数是多少．
<gadget id="calculator">10 / 5</gadget>
<output>2</output>

<gadget id="calculator">2 * 9</gadget>
<output>18</output>

<result>18</result>