Question 720605
Let {{{ x }}} = his age now
{{{ x + 20 }}} = his age 20 years hence
{{{ x - 12 }}} = his age 12 years ago
given:
{{{ x + 20 = 3*( x - 12 ) }}}
{{{ x + 20 = 3x - 36 }}}
{{{ 2x = 56 }}}
{{{ x = 28 }}}
He is 28 now
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check:
In 20 years he is 48
12 years ago he was 16
{{{ 48 = 3*16 }}}
{{{ 48 = 48 }}}
OK