Question

a boy walks to his school at a distance of 6km with a speed of 2.5km/hr and walks back with a constant speed of 5km/hr. His average speed for round trip expressed in km/hr is?

Answer 1

average speed = 
total distance travelled/total time taken 

total distance =6+6=12km 

time to school 
time =6/2.5=2.4 s 

time to home 
time!=6/4=1.5 s 

total time = 3.9 s 


average speed = 12/3.9=3.076 km/s 
=3076m/s approx

Answer 2

This question is very simple.

Average speed = Total Distance / Total Time Taken

We have given speeds S1 and S2

S1 = 2.5 km/hr

S2 = 5 km/hr

And Distance D1 and D2

D1 = 6 km

D2 = 6 km

Total Distance = D1 + D2 = 6 + 6 = 12 km

Now

T1 = D1/S1

T1 = 6/2.5 = 2.4 hr

T2 = D2/S2

T2 = 6/5 = 1.2 hr

Total Time = T1 + T2 = 2.4 + 1.2 = 3.6 hr

Now

Average Speed = Total Distance / Total Time = 12 / 3.6

Average Speed = 3.33 km/hr

i hope it will helpful for

@sushany❤❤