merlyn,
Alternatively, your average age could be 22. Take the sum of all your ages and divide by the number of ages.

print ave_age( 43 );
sub ave_age { ($_[0] * $_[0] + $_[0]) / 2 / $_[0] }
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Incidently, my average age using this formula is 14.5 which assumes you were never 0 years old.