SOLUTION: Jeremy is making a 665 mile trip. He drives for 5 hours at 55 mph. What is the average rate of speed he must drive to complete the total trip in 11 hours? Assume that a steady spee

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Question 600257: Jeremy is making a 665 mile trip. He drives for 5 hours at 55 mph. What is the average rate of speed he must drive to complete the total trip in 11 hours? Assume that a steady speed is maintained for the rest of the trip.
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
He drove 5 hours at 55 mph. So he drove d = rt = 55*5 = 275 miles so far.

He now has 665 - 275 = 390 miles left to go

So d = 390.

Since he wants to complete the trip in 11 hours, and he's already taken up 5 hours, he has 11 - 5 = 6 hours left.

So t = 6

Now use d = rt to solve for r


d = rt

390 = r*6

390/6 = r

65 = r

r = 65

So he must average 65 mph