Question 1026092
Let {{{ x }}} = number of buses they took
{{{ 9 - x }}} = number of cars they took
------------------
{{{ 45x + 5*( 9 - x ) = 165 }}}
{{{ 45x + 45 - 5x = 165 }}}
{{{ 40x = 120 }}}
{{{ x = 3 }}}
and
{{{ 9 - x = 6 }}}
They took 3 buses and 6 cars
-------------------------
check:
{{{ 3*45 = 135 }}}
{{{ 6*5 = 30 }}}
{{{ 135 + 30 = 165 }}}
OK