document.write( "Question 179315This question is from textbook Merrill Algebra 1
\n" ); document.write( ": I am confused about this question. In the book it says that the average is not 50 miles per hour. I need to know how to set up the problem to solve it:
\n" ); document.write( "Joan Bidney travels from Cincinnati to Winston-Salem at an average rate of 40 miles per hour and returns at an average rate of 60 miles per hour. What is her average speed for the trip? (Hint: the average speed is not 50 miles per hour.) \n" ); document.write( "

Algebra.Com's Answer #134224 by Mathtut(3670) $\"\"$ $\"About$

You can put this solution on YOUR website!
ok, lets call the distance d, the rate r, and the time t
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\n" ); document.write( "d=40t.....trip to
\n" ); document.write( "d=60t.....trip back
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\n" ); document.write( "solve for t
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\n" ); document.write( "t=d/40....trip to
\n" ); document.write( "t=d/60....trip back
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\n" ); document.write( "now lets take the time traveled for the entire to and back trip and multiply it by average rate for the whole trip which will be equal to 2d
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\n" ); document.write( " $\"%28%28d%2F40%29%2B%28d%2F60%29%29R=2d\"$
\n" ); document.write( ":
\n" ); document.write( " $\"%28%283d%2F120%29%2B%282d%2F120%29%29R=2d\"$ found common denominator on left
\n" ); document.write( ":
\n" ); document.write( " $\"%28%283%2B2%29%2F120%29R=2\"$ divided all terms by d
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\n" ); document.write( " $\"5R=240\"$ combined numerator on left and multiplied by 120 on both sides
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\n" ); document.write( " $\"highlight%28R=48%29\"$ mph average for whole trip
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