Question 535335
Let {{{ x }}} be his age now
{{{ x - 5 }}} is the man's age 5 years ago
given:
{{{ x/4 }}} is his niece's age now
{{{ x/4 - 5 }}} is his niece's age 5 years ago
{{{ x - 5 = 5*( x/4 - 5 ) }}}
{{{ x - 5 = (5/4)*x - 25 }}}
{{{ 4x - 20 = 5x - 100 }}}
{{{ -20 = x - 100 }}}
{{{ 100 - 20 = x }}}
{{{ x = 80 }}}
He is 80