The ratio of the two numbers of A and B is 3:5, and the number of A is 15. What is the sum of the two numbers of A and B?
甲乙两数的比是3：5，甲数是15，甲乙两数的和是多少．
<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">15 / (3/8)</gadget>
<output>40</output>

<result>40</result>