A jogger running at 9 kmph alongside a railway track in 240 metres ahead of the engine of a 120 metres long train running at 45 kmph in the same direction. In how much time will the train pass the joɡɡer?

A. 3.6 sec
B. 18 sec
C. 36 sec
D. 72 sec

Explanation
With 5 best steps
1.Data:
Speed 1=V₁= 9km/h
Distance 1=S₁= 240 m
Distance 2 =S₁= 120 m
Speed 2=V₂= 45km/h
Relative speed(V) = V₂_V₁
Relative speed (V)= 45km/h_9 km/h
Relative speed (V)=36km/h
Relative speed(V)= 36×1000m/3600Sec
Relative speed (V)= 36000m/3600Sec
Relative speed(V)= 10 m/sec
Covered distance(S)= 240m+120m
Covered distance (S)= 360m.
2. Required:
Time taken= T=??
3. Formula:
S= V×T
For T
T = S/V
4. Solution:
Putting values in formula.
T= 360 m/10 m/Sec
T= 36Sec
5. Result:
Time taken= T= 36 Sec