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
Algebra.Com
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
------------
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
===========
225/30 = 7.5 hours
225/50 = 4.5 hours
RELATED QUESTIONS
Two trains made the same 150-mile run. Since one train traveled 20 mph faster than the... (answered by ikleyn)
Two trains made the same 360-mile run. Since one train traveled 10 mph faster than the... (answered by ikleyn,Boreal)
Two trains made the same 315-mile run. Since one train traveled 10 mph faster than the... (answered by josgarithmetic)
Two trains made the same 315-mile run. Since one train traveled 10 mph faster than the... (answered by lwsshak3)
Two trains made the same 360-mile run. Since one train traveled 15 mph faster than the... (answered by josgarithmetic)
Two trains made the same 350-mile run. Since one train traveled 15 mph faster than the... (answered by umnikmo)
Two trains made the same 315-mile trip. Since one train traveled 10 mph faster than the... (answered by richwmiller)
Finding rates Two trains made the same 315-mile run. Since one train traveled 10mph... (answered by dkppathak)
suppose two trains leave a station at the same time, traveling in opposite directions.... (answered by Alan3354)