You want your total time to be
150/60 = 5/2 hours
Since time = distance/speed, you need
75/50 + 75/x = 5/2
x = 75
Imagine that you are driving 150 miles and you want your average speed for the trip to be 60 miles per hour.Imagine that you drive the first half (by distance) of the trip at 50 mph. How fast must you drive on the second half to make your average speed for the whole trip 60 mph? (Hint: The answer is NOT 70 mph.)
If it's not 70mph, what else could it possibly be?
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1 answer