Question

A train 77.5 m in length is running at the rate of 65 Kmph. Find the time taken by the train to pass the man walking in the same direction as the train @ 3 Kmph

Answer 1

speed of train=65kmph

distance=length of train=77.5m
speed relative to men=65-3
                                   =62kmph

                                   = 62*5/18
                                    =155/9 m /sec

Time = distance/speed
         = 77.5*9/155
         =4.5 sec

Answer 2

Answer: 4.1 seconds

Step-by-step explanation:

• We need to understand the concept of effective speed that if two body is travelling in the same direction then their effective speed is the sum of their speed and if they are moving in opposite direction then the effective speed will be the difference of their speed.
• Here the effective speed will be (65+3) km/hr

                                                             = 68 km/hr or 18.8 m/s

• Length of train= 77.5 m

• Time taken to cross the man= $\frac{77.5}{18.8}\ s$

                                                        = 4.1 seconds

• Hence the required answer is 4.1 seconds.

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