There are two natural numbers P and Q, and P◇Q means the average of P and Q, such as: 3◇5=4, according to this rule, what is the value of x in (5◇9)◇x=50.
有两个自然数P、Q，并且P◇Q表示P与Q的平均数，如：3◇5=4，按此规定计算，则(5◇9)◇x=50中x的值是多少．
<gadget id="calculator">5 + 9</gadget>
<output>14</output>

<gadget id="calculator">14 / 2</gadget>
<output>7</output>

<gadget id="calculator">100 - 7</gadget>
<output>93</output>

<result>93</result>