The ratio of the numbers A and B is 2:5. Given that the number B is 20, what is the sum of the numbers A and B?
甲、乙两数的比是2：5，已知乙数是20，甲、乙两数之和是多少．
<gadget id="calculator">20 / 5</gadget>
<output>4</output>

<gadget id="calculator">2 + 5</gadget>
<output>7</output>

<gadget id="calculator">4 * 7</gadget>
<output>28</output>

<result>28</result>