If the average of a and b is 6, what is the average of a+1 and b+3
如果a与b的平均数是6，那么a+1与b+3的平均数是多少
<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">12 + 4</gadget>
<output>16</output>

<gadget id="calculator">16 / 2</gadget>
<output>8</output>

<result>8</result>