SOLUTION: 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?

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?

Answer by lwsshak3(11628) (Show Source): You can put this solution on YOUR website!
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?
***
let x=speed Gerald drove to his parent's home
x+20=speed of Gerald's return trip
travel time=distance/speed
..
travel time to house-travel time of return trip=1 hr

LCD:x(x+20)
120(x+20)-120x=x(x+20)
120x+2400-120x=x^2+20x
x^2+20x-2400=0
(x+60)(x-40)=0
x=-60 (reject)
or
x=40
speed Gerald drove to his parent's home=40 mph
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