A 300 metre long train crosses a platform in 39 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform?
A. 320 m
B. 350 m
C. 650 m
D. Data inadequate
Answer: Option B
Solution(By Examveda Team)
$$\eqalign{ & {\text{Speed}} = {\frac{{300}}{{18}}} \,{\text{m/sec}} \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{{50}}{3}\,{\text{m/sec}} \cr & {\text{Let}}\,{\text{the}}\,{\text{length}}\,{\text{of}}\,{\text{the}}\,{\text{platform}}\,{\text{be}}\,x\,{\text{metres}}{\text{.}} \cr & {\text{Then}}, {\frac{{x + 300}}{{39}}} = \frac{{50}}{3} \cr & \Rightarrow 3\left( {x + 300} \right) = 1950 \cr & \Rightarrow x = 350\,m. \cr} $$Join The Discussion
Comments ( 2 )
Related Questions on Problems on Trains
A. 120 metres
B. 180 metres
C. 324 metres
D. 150 metres
A. 45 km/hr
B. 50 km/hr
C. 54 km/hr
D. 55 km/hr
A. 200 m
B. 225 m
C. 245 m
D. 250 m
Speed of train = 300/18= 50/3 m/s
Time taken by train to cover platform= 39-18=21s
Platform length = speed * time
= 50/3 * 21= 350m
300/18=16.66
that mean in 18sec train cover only 16.66 m distance
and remaining time is 39-18=21
Therefore 21x16.66=350 m
So the platfom is 350m