SOLUTION: A family is on a road trip. The speed limit during the first 160 miles of the trip is 55 mph, and the speed limit during the last 240 miles is 65 mph. How many miles per hour over

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Question 1164394: A family is on a road trip. The speed limit during the first 160 miles of the trip is 55 mph, and the speed limit during the last 240 miles is 65 mph. How many miles per hour over the speed limits must they drive in order to arrive at their destination in 6.5 hours?
Found 2 solutions by Boreal, ikleyn:
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
time for the first 160 miles is 160/55 or 2.909 hours
They have 3.591 hours left to go 240 miles, or an average speed of 66.83 mph.
They have to go over the limit an average of 1.83 mph.

Answer by ikleyn(52786) About Me  (Show Source):
You can put this solution on YOUR website!
.

    160%2F%2855%2Bx%29 + 240%2F%2865%2Bx%29 = 6.5  hours


Solve for x.

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Actually,  the meaning of this problem is  DARK,  and,  probably,  due to this reason it would be better do not even try to solve it.