First. The average of B's two numbers is 42, A. The ratio of the two numbers of B is 3:4, what is the number of A?
甲．乙两数的平均数是42，甲．乙两数的比是3：4，甲数是多少．
<gadget id="calculator">42 * 2</gadget>
<output>84</output>

<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">84 * (3/7)</gadget>
<output>36</output>

<result>36</result>