SOLUTION: A train goes twice as fast downhill as it can go uphill, and 2/3 feet as fast uphill as it can go on level ground. if it goes 120 miles per hour downhill, how long will it take to

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Question 1150546: A train goes twice as fast downhill as it can go uphill, and 2/3 feet as fast uphill as it can go on level ground. if it goes 120 miles per hour downhill, how long will it take to travel 45 miles per flat land?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +r%5B1%5D+ =rate going uphill
+120+%2F+r%5B1%5D+=+2%2F1+
+r%5B1%5D+=+60+
————————-
Let { r[2] = rate on flat land
+60%2Fr%5B2%5D+=+%282%2F3%29%2F1+
+r%5B2%5D+=+90+
———————-
+d+=+r%5B2%5D%2At+
+45+=+90t+
+t+=+1%2F2+
It takes a half hour to go 45 miles