Question 467650: Hi, I have attempted the problem but really have only done some unit conversions. I can't get past my confusion on how to handle the two different times in two different time zones the trains depart. Any help would be greatly appreciated. I am assume after the time issue is resolved the formula D=rt can be used.
Two trains are on the same track between San Francisco and New York. One train leaves San Francisco, heading east, at 8AM PDT on a Tuesday, and goes 45[kph] for 2 hours, and then speeds up to 95[kph]. Another train leaves New York, heading west, at 9AM CST on the same Tuesday, going 35[mph] for 100 miles, and then speeds up to 80[mph]. The train going west uses a steam locomotive, and the train going east uses a diesel. Assume that there are 2905 miles between San Francisco and New York, going through Des Moines and Salt Lake City.
When will the trains meet?
Thanks.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Two trains are on the same track between San Francisco and New York. One train leaves San Francisco, heading east, at 8AM PDT on a Tuesday, and goes 45[kph] for 2 hours, and then speeds up to 95[kph]. Another train leaves New York, heading west, at 9AM CST on the same Tuesday, going 35[mph] for 100 miles, and then speeds up to 80[mph]. The train going west uses a steam locomotive, and the train going east uses a diesel. Assume that there are 2905 miles between San Francisco and New York, going through Des Moines and Salt Lake City.
When will the trains meet?
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Time difference between 8AM PDT and 9AM CST
CST is 2 hrs before PDT
At 9AM CST it is 7 AM PDT
The west bound train has a 1 hr. advantage on the east bound train
----------------
East Bound train:
distance = 2*45+ 95t
--------
West Bound train:
100miles/35 mph = 2.86 hrs
distance = 100 + 80(t+1-2.86)
distance = 100 + 80(t-1.86)
==============================
Equation:
90 + 95t + 100 + 80t - 148.8= 2905
41.21+175t = 2905
175t = 2863.8
t = 16.36 hrs
t-1 = 15.36 hrs.
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Time they will meet: 9AM CST + 15.36 hrs = 1:22AM CST on Wednesday
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Cheers,
Stan H.
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