Question

Abdul while driving to school , computers the average speed for his trip to be 20 km/h. on his trip alone the same route less traffic and the avarage speed is 30km/h . what is the avarage speed of abul trip.

Answer 1

While driving to school

Average speed of Abdul’s trip = 20 km/h



Total distance = Distance travelled to reach school = d

Let total time taken = t1



 …(i)

Case II: While returning from school

Total distance = Distance travelled while returning from school = d

Now,total time taken = t2

30=dt2t2=d30  ..... (ii)30=dt2t2=d30  ..... (ii)

 



Where,

Total distance covered in the trip = d + d = 2d

Total time taken, t = Time taken to go to school + Time taken to return to school

= t1 + t2



From equations (i) and (ii),

Average Speed=2dd20+d30=23+260Average Speed=1205=24 m/s