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Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - General Questions (Q.No. 21)
Problems on Trains
21.
How many seconds will a 500 metre long train take to cross a man walking with a speed of 3 km/hr in the direction of the moving train if the speed of the train is 63 km/hr?
25
30
40
45
Answer: Option
Explanation:

Speed of the train relative to man = (63 - 3) km/hr
= 60 km/hr
= ( 60 x 5 ( m/sec
18
= ( 50 ( m/sec.
3
Therefore Time taken to pass the man
= ( 500 x 3 ( sec
50
= 30 sec.

Discussion:
44 comments Page 3 of 5.
Saurav dey said:   10 years ago
Distance/speed.
Vipul said:   10 years ago
Which is this a-b/u-v formula? Please explain.
Niyati said:   10 years ago
Why take 5/18?
Manju said:   9 years ago
Why 50/3 is taken as 3/50?
Hariharan.p(sphari23) said:   9 years ago
Same direction man&train moving = a+b/u-v.

500/63-3*5/18 m/sec.

=> 30 sec.
Aliza Mir said:   9 years ago
Here speeds of train and man are accordingly subtracted because the reference point.
i.e. man is not stationary. Had it been stationary the formula to be applied would have been u - v m/sec. Since, this is not the case scenario so the formula applied is u= v - x m/sec.
VINAYAK PB said:   9 years ago
First of all, calculate 1m per second that is 60000/3600 = 16.6m/s.

So for 500m it, 500/16.6 = 30sec.
Raghu said:   8 years ago
Here why we didn't add 500 to the distance, total distance = 500 + 500 = 10000?

Please explain.
Naresh said:   7 years ago
Instead of subtracting 63-3, I first converted 63kmph and 3kmph to its equivalent m/s and then I subtracted. The answer I got was not equal to 60*(5/18). Why? Can someone explain?
(1)
Sarang said:   7 years ago
Distance =speed *time.
500=60-3km/h*time,
500=60*5/18*time,
500=60*.277*time,
500=16.62*time,
Time=500/16.62=30s.
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