SOLUTION: An express train travels 380 miles between two cities. During the first 120 miles of a trip, the train traveled through mountainous terrain. The train traveled 12 miles per hour sl
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Question 957374: An express train travels 380 miles between two cities. During the first 120 miles of a trip, the train traveled through mountainous terrain. The train traveled 12 miles per hour slower through mountainous terrain than through level terrain. If the total time to travel between the cities was 8 hours, find the speed of the train on level terrain.
Can't seem to solve this one Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website!
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Let = the train's rate in mi/hr on level terrain = the train's rate in mi/hr in mountainous terrain
Let = the train's time in hrs on mountainous terrain = the train's time on level terrain
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For mountainous terrain:
(1)
For level terrain:
(2)
(2)
---------------------------
(2)
By substitution:
Multiply both sides by
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Use quadratic formula
----------------- mi/hr
This can't be the answer, since I have to subtract mi/hr
to get rate on mountainous terrain, so mi/hr mi/hr
The speed on level terrain is 52 km/hr
check:
(1)
(1)
(1)
(1) hrs
and
(2)
(2)
(2)
(2) hrs
OK
Hope I got it!
