Awk: make an average in file with both number and string
<p>here is my problem (not sure that my title was clear), I have to display an average of number in a file. However there is string in the file too.<br>
<pre>file: test  </p>

<code>Richie;jack;27 Yo;07Richiej@gmail.com  
Cash;tom;29 Yo;Ctom01@gmail.com  
Megane;susan;37 Yo;meganeSusan@gmail.com   
</code></pre>

<p>...<br>

it has to display the average age of the people in my file, I'm not supposed to know how many people there are.</p>

<p>I thought about using RegEx to only get number in my 3rd field, but got errors each time.<br>
    awk 'BEGIN{FS=";"} /      /          </p>