A train, 300m long, passed a man, walking along the line in the same direction at the rate of 3 kmph in 33 seconds. The speed of the train is:
A. 30 kmph
B. 32 kmph
C. $$32\frac{8}{{11}}$$ kmph
D. $$35\frac{8}{{11}}$$ kmph
Answer: Option D
Solution(By Examveda Team)
Let the speed of train = x km/ hrLength of train = 300 metres
Their relative speed in same direction
= (x - 3) km/hr
According to the question,
$$\frac{{\left( {300 + 0} \right)m}}{{\left( {x - 3} \right) \times \frac{5}{{18}}m/s}} = 33$$
[Here man's length is 0 metre]
$$\eqalign{ & \frac{{100 \times 18}}{{5x - 15}} = 11 \cr & 1800 = 55x - 165 \cr & 55x = 1965 \cr} $$
∴ Speed of the train = $$\frac{{1965}}{{55}}$$ = $$35\frac{8}{{11}}$$ kmph
This Question Belongs to Arithmetic Ability >> Speed Time And Distance
Join The Discussion
Comments ( 3 )
Related Questions on Speed Time and Distance
A. 48 min.
B. 60 min.
C. 42 min.
D. 62 min.
E. 66 min.
A. 262.4 km
B. 260 km
C. 283.33 km
D. 275 km
E. None of these
A. 4 hours
B. 4 hours 30 min.
C. 4 hours 45 min.
D. 5 hours
300*18/(x-3)*5=33.
The speed of the man is 3km/hr = 0.83m/sec
therefore in 33 secs he will move = 0.83x33 = 27.5m
The total distance covered by the train in 33 secs is = (300+27.5)m = 327.5m
therefore the speed of the train is = (327.5x3600) / (33x1000) = 35(8/11) Km/hr.
A train, 300m long, passed a man, walking along the line in the same direction at the rate of 3 kmph in 33 seconds. The speed of the train is:
please explain it i find the solution but i didn't get it. why they are supposing x if speed of train is already known