<PRE><B>Question 961399</B>
[ distance ] = [ rate ] x [ time ]
{{{ d = r*t }}}
Divide both sides by {{{ t }}}
{{{ r = d / t }}}
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given:
{{{ d = 3 + 1/2 }}}
{{{ t = 1/3 }}}
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Note that:
{{{ ( 2d ) / ( 2t ) = d/t }}}, 
so, I can say:
{{{ r = 7 / ( 2/3 ) }}}
Multiply the top and bottom of this fraction by {{{ 3 }}}
{{{ ( 3*7 ) / 2 = 21/2 }}}
{{{ 21/2 = 10 + 1/2 }}}
The first part of the race was run at a rate of:
10 and 1/2 miles/hour
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