The average of the two numbers of A and B is 20, the ratio of A and B is 2:3, what is A's number?
甲乙两数的平均数是20，甲数与乙数的比是2：3，甲数是多少．
<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">20 * (2/5) * 2</gadget>
<output>16</output>

<result>16</result>