Question

aeroplane flies around a square field ABCD of each side 1000km. It speed along AB is 250 1
kmh , along BC 600 1
kmh , along CD 200 1
kmh and along DA 100 1
kmh . Its average speed over the entire trip is ___________ ( in 1
kmh )

Answer 1

Answer:

Hi !

Let us look at the simplest approach to solve this question!

Concept : Average Speed = Total distance/Total Time.

Let us assume that the side of the square = LCM (200,400,600,800)= 2400 km.

Now, time taken across the first side = distance/speed = 2400/200 = 12 hr.

Similarly, times taken across the other three sides = 2400/400 = 6 hrs, 2400/600 = 4 hrs and 2400/800 = 3 hrs.

Thus, total distance = 2400*4 = 9600 km.

Also, total time = (12+6+4+3) = 25 hours.

Thus, average speed from the above concept = 9600/25 = 384 km/hr.

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Hope this helps! :)