physics question

Question

A car is making a 58 mi trip.in the first half of the time its speed is 11.00 mph and in the second half of the time its speed is 36.00 mph.

What is the total time in hours of the trip? Keep two decimal places.

Answer 1

Let T = total time for the trip (hours)

Then (T/2)11 + (T/2)36 = 58 or (11/2)T + (36/2)T = 58

or (47/2)T = 58

and T = 2.47 hours trip time

Answer 2

Suppose we let the time for each half =t

We know the total distance is 58 miles. By looking at each half distance and velocity we get

11t+36t = 58

47t=58

t= 58/47 hours = 1.234 hours

Total Time = 2t = 2.47 hours