Answer:
The average speed can be calculated by dividing the total distance covered by the total elapsed time.
The problem suggests that there are three segments of Alfred's travel:
(a) First segment: Alfred drove 1 1/2 hours at375 km/h. Since distance = speed × time, the distance covered in this part of the travel was d=75 kph × 1.5 hours = 112.5 km
(b) Second segment: Alfred drove 120 kilometers at 60 km/hr. To compute for how much time he spent on this part of the travel, we use the formula
time = distance ÷ speed. So time = 120 km ÷ 60 kph = 2 hours.
(c) Third Segment: He drove for 30 minutes (0.5 hr) at 65 km/hr. For us to know how far (distance) he traveled, we use the same formula of distance we used in (a). So, distance = 65 kph × 0.5 hr = 32.5 km.
Putting all distances together, we have 112.5 km + 120 km + 32.5 km = 256 km as the total distance covered
Doing the same for the total time, we have 1.5 hours + 2 hours + 0.5 hours = 4 hours as the total time spent.
Since the average speed is the total distance ÷ total elapsed time, we have 256 km ÷ 4 hours = 64 kph.
So the average speed is 64 km/hr.
Step-by-step explanation:
