Question

a car travel 100 km at a speed of 60 km per hour and return with a speed of 40 km per hour calculate the average speed for the whole journey

Answer 1

solution.

time taken to travel 100km at 60 km/h

= 100/60= 5/3

Time taken to travel 100km at 40km/h

= 100/40= 5/2

now, total time taken= 5/3+ 5/2

= (10+15)/6

= 25/6

Now, Avenge Speed = 200*6/25

= 8*6

= 48km/h

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hope it helps you☺✌✌

Answer 2

Hello Mate!

As we know that

Speed = Distance /Time
60 = 100/t1
t1 = 100/60
= 10/6 = 5/3 = 1.6 h

40 = 100/ t2
t2 = 100/40 = 5/2 = 2.5 h

Average Speed = Total Distance / Total Time

= ( 100 + 100 ) / ( 1.6 + 2.5 )
= 200/ 4.1 = 48.9 km / h or approximately 50 km/h

Hope it helps☺!✌