Question 573710
Let {{{ a }}} = liters removed from tank a
and added to tank b
given:
{{{ (1/3)*( 23 - a ) = 1 + a }}}
{{{ 23 - a = 3*( 1 + a ) }}}
{{{ 23 - a = 3 + 3a }}}
{{{ 4a = 20 }}}
{{{ a = 5 }}} 
5 liters must be removed from tank a and poured into tank b
check:
{{{ 23 - 5 = 18 }}} ( left in a )
{{{ 1 + 5 = 6 }}} ( put in b )
Tank b now has 1/3 the water in tank a