A train travels from one station to another
at a speed of 40 kmph and returns to the
first station at a speed of 60 km ph. Then
average speed of the train is....... kmph.
Answers
Answered by
0
Answer:
48 km/h
Explanation:
Net displacement of the train in coming back to the first station is zero i.e. S=0 .
Average velocity V
avg
=
t
S
=0
Average speed of the train when in moving equal distances is given by ∣V∣
avg
=
v
1
+v
2
2v
1
v
2
⟹ ∣V∣
avg
=
40+60
2×40×60
=48 km/h
Answered by
1
Average speed =
Total Distance ÷ Total Time
Let 'D 'be the distance from one station to another
Let t1 & t2 be the time taken to reach and return respectively
first case
speed 40 kmph
40= D÷ t1
second case
speed 60 kmph
60= D/t2
you have D= 40*t1
also D = 60*t2
if you equate it you have t2 = (2/3) t1
u have Total Distance = D+D = 2D
Total Time= t1 + t2 = t1 + (2/3)t1 = (5/3)t1
substituting
Average speed = 2*(40 t1) ÷ (5/3) t1
Average speed = 48 kmph.....
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