The ratio of number A to number B is 3:5, and how much of the sum of these two numbers is accounted for by number B.
甲数与乙数的比是3：5，乙数占这两个数之和的多少．
<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<result>5/8 = around 0.625</result>