Question 943247
{{{ t[1] = 120 / r[1] }}}
{{{ t[1] = 120 / 70 }}}
{{{ t[1] = 12/7 }}} hr
This is the time for you to reach destination
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For the car passing you:
{{{ 120 = r[2]*( 36/21 - 1/3 )}}
( note that {{{ 20 }}} min = {{{ 1/3 }}} hr )
{{{ 120 = r[2]*( 36/21 - 7/21 ) }}}
{{{ 120 = r[2] *( 29/21 ) }}}
{{{ r[2] = ( 21/29 )*120 }}}
{{{ r[2] = 86.897 }}}
The passing car must travel at 86.897 mi/hr