document.write( "Question 853216: Gerald drove 120 miles to his parent's home. His return trip took 1 hour less because he drove 20 mph faster. How fast did Gerald drive going to his parents house?
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Algebra.Com's Answer #513993 by lwsshak3(11628) $\"\"$ $\"About$

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Gerald drove 120 miles to his parent's home. His return trip took 1 hour less because he drove 20 mph faster. How fast did Gerald drive going to his parents house?
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\n" ); document.write( "let x=speed Gerald drove to his parent's home
\n" ); document.write( "x+20=speed of Gerald's return trip
\n" ); document.write( "travel time=distance/speed
\n" ); document.write( "..
\n" ); document.write( "travel time to house-travel time of return trip=1 hr
\n" ); document.write( " $\"120%2Fx-120%2F%28x%2B20%29=1\"$
\n" ); document.write( "LCD:x(x+20)
\n" ); document.write( "120(x+20)-120x=x(x+20)
\n" ); document.write( "120x+2400-120x=x^2+20x
\n" ); document.write( "x^2+20x-2400=0
\n" ); document.write( "(x+60)(x-40)=0
\n" ); document.write( "x=-60 (reject)
\n" ); document.write( "or
\n" ); document.write( "x=40
\n" ); document.write( "speed Gerald drove to his parent's home=40 mph \n" ); document.write( "

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