Question 1005368

In the 1st 1/2 hr, {{{ d = 200*.5 }}}
{{{ d = 100 }}}
In the last 1/2 hr, {{{ d = 100 }}} also
{{{ 2100 - 200 = 1900 }}} mi is flown at
the other constant speed
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{{{ 1000 - 100 = 900 }}} mi near the end of the trip is
covered in {{{ 2 - .5 = 1.5 }}} hrs
{{{ 900/1.5 = 600 }}} mi/hr is the
other constant speed
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Let {{{ t }}} = time of flight except for the 1st
1/2 hr and last 1/2 hr
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{{{ 1900 }}} is the miles covered at {{{ 600 }}} mi/hr
{{{ 1900 = 600t }}}
{{{ t = 3.1667 }}}
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{{{ 3.1667 + .5 + .5 = 4.1667 }}}
{{{ .1667*60 = 10 }}}
This is 4 hrs and 10 minutes for the entire flight
Hope I got it!