SOLUTION: Two trains make the same 225 mph run. Since one train travels 20 mph faster than the other one it arrive 3 hours earlier. What is the speed of the trains
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Question 918996: Two trains make the same 225 mph run. Since one train travels 20 mph faster than the other one it arrive 3 hours earlier. What is the speed of the trains Answer by Alan3354(69443) (Show Source):
You can put this solution on YOUR website! Two trains make the same 225 mph run. Since one train travels 20 mph faster than the other one it arrive 3 hours earlier. What is the speed of the trains
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r = slower speed
3 + 225/r = 225/(r-20)
(3r+225)/r = 225/(r-20)
225r = (3r+225)*(r-20)
75r = (r+75)*(r-20)
75r = r^2 + 95r - 1500
r^2 + 20r - 1500 = 0
(r + 50)*(r - 30) = 0
r = 30 mi/hr
--> 30 & 50 mi/hr
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225/30 = 7.5 hours
225/50 = 4.5 hours
