document.write( "Question 1041198: Jenny walks 5 kilometers from her house to Star SuperMall to buy a new bike which she uses to return home. She averaged 10 kilometers faster on her bike than on foot. If her total trip took 1 hour and 20 minutes, what is her walking speed in kph? Use the formula v = d/t . \n" ); document.write( "

Algebra.Com's Answer #656150 by jorel555(1290) $\"\"$ $\"About$

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If v=d/t; then t=d/v. Since we know Jenny traveled 5 kilometers both ways; let n be her walking speed. So
\n" ); document.write( "5/n+5/(n+10)=4/3 hours
\n" ); document.write( "15/n+15/(n+10)=4
\n" ); document.write( "15(n+10)+15n=4(n²+10n)
\n" ); document.write( "30n+150=4n²+40n
\n" ); document.write( "4n²+10n-150=0
\n" ); document.write( "Using the quadratic formula, we get
\n" ); document.write( "n=5 or -7.5
\n" ); document.write( "So her speed on foot was 5 kmh, and on bike it was 15 kmh. ☺☺☺☺ \n" ); document.write( "

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