SOLUTION: A passenger train making a 240 km trip traveled the first 120 km at 75 km/h. At what speed must it travel the second 120 km in order to average 100 km/h for the entire trip? I

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Question 370696: A passenger train making a 240 km trip traveled the first 120 km at 75 km/h. At what speed must it travel the second 120 km in order to average 100 km/h for the entire trip?

I think I am confused on the set up and that is what's messing me up. Any help would be great!
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi,

Traveling 120km for each of the speeds (this is 'not' a question of weighted averages 

Let x represent speed traveled for the second half of the trip

%2875kmph+%2B+x%29%2F2+=+100kmphr

75 + x = 200

x = 125kmph, the travel speed necessary the second half of the trip to average 100kmph