Question 548824
Let the speed of the slower car = {{{ s }}}
the speed of the faster car is {{{ s + 12 }}}
They are moving apart at the sum of their speeds
given:
{{{ 396 = ( s + s + 12 )*3 }}}
{{{ 3*( 2s + 12 ) = 396 }}}
{{{ 6s + 36 = 396 }}}
{{{ 6s = 360 }}}
{{{ s = 60 }}}
{{{ s + 12 = 72 }}}
The car going south has speed of 72 mi/hr
The car going north has speed of 60 mi/hr