SOLUTION: a train made a trip of 600 miles between 2 cities. if it averaged 10 miles per hour more, it would have required 2 hours less to take the trip. find the rate of speed of the train.

Question 749464: a train made a trip of 600 miles between 2 cities. if it averaged 10 miles per hour more, it would have required 2 hours less to take the trip. find the rate of speed of the train.
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = the 1st speed in mi/hr
= the increased speed in mi/hr
Let = the train's time at mi/hr
= the train's time at mi/hr
----------------------
given:
(1)
(2)
----------------------------
(2)
(2)
(2)
and,
(1)
(1)
(2)
(2)
(2)
(2)
(2)
Use quadratic formula

( can't use negative square root )

and
(1)
(1)
(1)
The speed of the train is 50 mi/hr
check:
(1)
(1)

and
(2)
(2)
(2)
(2)
OK