Question 938123
At {{{ 70 }}} mi/hr:
{{{ 60 = 70t }}}
{{{ t = 60/70 }}} hrs
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At {{{ 75 }}} mi/hr:
{{{ 60 = 75t }}}
{{{ t = 60/75 }}} hrs
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{{{ 60/70 - 60/75 = 60*( 1/70 - 1/75 ) }}}
{{{ 60*( 1/5)*( 1/14 - 1/15 ) }}}
{{{ 12*( 1/14 - 1/15 ) }}} hrs
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Convert to minutes:
( min ) = ( hrs )*( min/hrs )
{{{ 12*( 60/14 - 60/15 ) }}}
{{{ 12*( ( 4 + 4/14 ) - 4 ) }}}
{{{ 12*( 2/7 ) = 24/7 }}} min
{{{ 24/7 = 3 + 3/7 }}} min
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Convert {{{ 3/7 }}} to sec
{{{ (3/7)*60 = 25.7 }}} sec
You save 3 min 26 sec
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check:
{{{ ( 24/7 )/60 = ( 6/7 )/15 }}}
{{{ ( 6/7 )/15 = 6/105  }}} hrs
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{{{ 60/70 - 60/75 = 6/105 }}}
{{{ 10/70 - 10/75 = 1/105 }}}
{{{ .142857 - .133333 = .0095238 }}}
{{{ .009524 = .0095238 }}}
close enough