Question 1057615
Average speed is always
[ total distance traveled ] / [ total time spent traveling ]
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{{{ t[1] = d/r }}}
{{{ t[1] = 1/30 }}} hr
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{{{ t[2] = d/r }}}
{{{ t[2] = 1/60 }}} hr
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Average speed  = {{{ (( 1 + 1 )) / (( 1/30 + 1/60 )) }}}
{{{ 2 / (( 2/60 + 1/60 )) }}}
{{{ 2 / (( 3/60 )) }}}
{{{ 2 / (( 1/20 )) }}}
{{{ 2*20 = 40 }}}
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The average speed is 40 mi/hr