Problema Solution
A person travels by car from one city to another with different constant speeds between pairs of cities. She drives for 15.0 min at 70.0 km/h, 18.0 min at 70.0 km/h, and 50.0 min at 35.0 km/h and spends 25.0 min eating lunch and buying gas.
(a) Determine the average speed for the trip.
Answer provided by our tutors
the average speed of the trip v= (total distance)/(total time)
the total distance = 70*(15/60) + 70*(18/60) + 35*(50/60) = 203/3 km
total time = 15 + 18 + 50 + 25 = 105 min = 108/60 h
v = (203/3)/(108/60)
v = 37.59 km/h
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the average speed of the trip is 37.59 km/h.