A train crosses a man and a woman walking on a platform at the rate of 3kmph and 6kmph in opposite direction taking 36sec and 30sec. what is the length of the train?Question 19Answera.None of theseb.300mc.100md.180m

To solve this problem, we need to use the formula for speed, which is distance/time.

1. When the train crosses the man:

The man is walking at a speed of 3 km/h in the opposite direction to the train. This means that the relative speed of the train to the man is the speed of the train plus the speed of the man.

We don't know the speed of the train yet, so let's call it T km/h. Therefore, the relative speed is T + 3 km/h.

The time it takes for the train to cross the man is 36 seconds, which is 36/3600 hours (since there are 3600 seconds in an hour).

So, we can set up the equation (T + 3) = d / (36/3600), where d is the length of the train.

2. When the train crosses the woman:

The woman is walking at a speed of 6 km/h in the opposite direction to the train. This means that the relative speed of the train to the woman is the speed of the train plus the speed of the woman.

Again, the relative speed is T + 6 km/h.

The time it takes for the train to cross the woman is 30 seconds, which is 30/3600 hours.

So, we can set up the equation (T + 6) = d / (30/3600).

3. Solving the equations:

We now have two equations with two unknowns (T and d), which we can solve simultaneously.

From the first equation, we can express d as d = (T + 3) * (36/3600).

Substituting this into the second equation gives us (T + 6) = (T + 3) * (36/30).

Solving this equation gives us T = 54 km/h.

Substituting T = 54 km/h back into the first equation gives us d = (54 + 3) * (36/3600) = 0.57 km = 570 m.

So, the length of the train is 570 m.

However, this option is not available in the given choices. Therefore, the answer is a. None of these.