document.write( "Question 384402: a man travels at certain distance at the rate of 70km/hour and return at the same point at the rate of 55 km/hour .What is the average speed of the journey ? \n" ); document.write( "
Algebra.Com's Answer #272132 by mananth(16949)\"\" \"About 
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distance = x
\n" ); document.write( "rate = 70 km/h
\n" ); document.write( "..
\n" ); document.write( "time x/70
\n" ); document.write( "..
\n" ); document.write( "return
\n" ); document.write( "time= x/55
\n" ); document.write( "...
\n" ); document.write( "Total Average rate = total distance/total time
\n" ); document.write( "=2x/(x/70+x/55)
\n" ); document.write( "=2x/(125x/3850)
\n" ); document.write( "=2x*3850/125x
\n" ); document.write( "=61.5 km/h
\n" ); document.write( "..
\n" ); document.write( "There is an easy solution.
\n" ); document.write( "let him drive for 1 hour
\n" ); document.write( "so forward journey he takes 1 hour.
\n" ); document.write( "distance he travels = 70 km
\n" ); document.write( "RETURN
\n" ); document.write( "distance = 70
\n" ); document.write( "rate = 55
\n" ); document.write( "time = 70/55= 1.27 hours
\n" ); document.write( "Total time taken = 1+1.27= 2.27 hours
\n" ); document.write( "total distance = 140 km
\n" ); document.write( "rate = 140/2.27
\n" ); document.write( "average rate for entire journey = 61.6 km/h
\n" ); document.write( "...
\n" ); document.write( "m.ananth@hotmail.ca \n" ); document.write( "
\n" );