Question 1037383
Average speed is always:
[ total distance traveled ] / [ total time spent traveling ]
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1st part of trip:
{{{ 100 = 65*t }}}
{{{ t = 100/65 }}}
{{{ t = 1.53846 }}}
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{{{ 80 = 75t }}}
{{{ t = 80/75 }}}
{{{ t = 1.06667 }}}
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Ave speed = {{{ ( 100 + 80 ) / ( 1.53846 + 1.06667 ) }}}
{{{ 180 / 2.60513  = 69.09453 }}}
Average speed was 69.09453 mi/hr