Question 888597
His time for the first {{{ 278 }}} km was:
{{{ 27 = 15*t }}}
{{{ t = 27/15 }}}
{{{ t = 1.8 }}} hrs
From 1 PM to 4 PM is {{{ 3 }}} hrs
He has {{{ 3 - 1.8 = 1.2 }}} hrs to get to his final stop
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Let {{{ s }}} = the speed he needs for last {{{ 30 }}} km
{{{ 30 = s*1.2 }}}
{{{ s = 30/1.2 }}}
{{{ s = 25 }}} km/hr