The ratio of the numbers A and B is 3:4, the number B minus the number A is 20.5, what is the number B?
甲、乙两数的比是3：4，乙数减甲数得20.5，乙数是多少．
<gadget id="calculator">4 - 3</gadget>
<output>1</output>

<gadget id="calculator">20.5 / 1</gadget>
<output>20.5</output>

<gadget id="calculator">20.5 * 4</gadget>
<output>82</output>

<result>82</result>