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

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">20 * 2 * (3/5)</gadget>
<output>24</output>

<result>24</result>