SOLUTION: I do not know how to go about solving this problem. "You drive to the city at an average speed of 40km/h and return at an average speed of 60km/h. Find your average speed for the

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Question 343254: I do not know how to go about solving this problem. "You drive to the city at an average speed of 40km/h and return at an average speed of 60km/h. Find your average speed for the entire trip? Explain why the answer is not 50km/h"
when i read the problem i assumed the answer was 50km/h because that was the average between the two. But after i read the last sentence, it changed my view on how to solve the problem. I need help on the process to answer the problem.
Answer by mananth(12270) About Me  (Show Source):
You can put this solution on YOUR website!
+speed+=+distance+%2F+time
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you will see that speed is a function of time and distance.
speed varies with time, distance being same.
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In the problem the distance is same but the time taken is different.
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If the city was 120 miles
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time going will be 120/40 = 3hours
time returning = 120/60 = 2hours
Total 5 hours.
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Distance is 240
time = 5
speed = 240/5
speed = 48 mph is the average speed