Question 489767
Let {{{ a }}} = Alvin's age now
Let {{{ b }}} = Ben's age now
given:
{{{ a = 4b }}}
{{{ a - 5 + b - 5 = 45 }}}
By substitution:
{{{ 4b - 5 + b - 5 = 45 }}}
{{{ 5b - 10 = 45 }}}
{{{ 5b = 55 }}}
{{{ b = 11 }}}
and, since
{{{ a = 4b }}}
{{{ a = 44 }}}
Alvin is 44 now
Ben is 11 now