A train moves past a telegraph post and a bridge 264 m long in 8 seconds and 20 seconds respectively. What is the speed of the train?
A. 69.5 km/hr
B. 70 km/hr
C. 79 km/hr
D. 79.2 km/hr
Answer: Option D
Solution (By Examveda Team)
Length of the Bridge = 264 m.Time taken to pass the bridge = 20 sec.
Time taken to passe the post = 8 sec.
Length of the train = X m (Let.)
To pass the bridge train need to cover Train's length + Bridge legnth (X + 264).
Speed = Distance covered / time taken
Now,
X/8 = (264 + X)/20
20X = 264 *8 + 8X
20X - X = 264 *8
12X = 264 *8
X = (264 *8)/12
X = 176 m.(length of the train)
Speed of the train = 176/8 = 22 m/sec = (22*18)/5 = 79.2 Kmph.
This Question Belongs to User Ask Question >> Miscellaneous
Why at the end 8sec is taken as time
Why 20sec is not taken.
A train passes a telegraph post in 8 seconds and a 264 m long bridge in 20 seconds. What is the length of the train?
this problem i not understant pls clear teaching
please write answers in bold letters.