The correct option is (C).

Answer with explanation:

Length of the train is equal to the distance covered by train to cross the pole. So, we will find the distance travelled by the train in 7 seconds by applying the following formula:

Distance= Speed x Time

Speed is given in Km/hr so we will convert it into m/s as answers are given in meters.

Speed=90*  5/18 = 25 m/s

Time = 7 seconds

Distance = 25 * 7= 175 meters

The correct option is (C).

Answer with explanation:

The distance covered by train when it crosses the bridge is equal to the sum of length of the train and length of the bridge.

Speed of train in m/s= 50*

Time = 40 seconds

Let the length of the bridge is X.

(length of bridge+ length of train)/ Time taken to cross the bridge= speed of train

(x+150)/45= 125/9= speed of train

9(X+150) = 45×125

9X+450= 5625

9X= 5625 – 450

9X=5175

X=5175/9= (speed of train)

The correct option is (B).

Answer with explanation:

Speed of train in m/s = 120 x 5/18 = 50/3 m/s

Distance covered to cross the platform is equal to the sum of length of the train and length of the platform.

So, distance= 150+100 = 250 meters

Time =Distance/Speed

= 250 *3/100

=750/100= 7.5 seconds

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The correct option is (D).

Answer with explanation:

Time =Distance covered/ Speed

In this problem, both the train and man are in motion so we will find the relative speed of the train. They are moving in the opposite direction, so the relative speed = (speed of train + speed of man)

Relative Speed: (80+10) = 90 km/hr

Relative Speed in m/s= 90*5/18 = 225/9 m/s 

Distance covered to cross the man = length of the train (200 meters)

Time =200/(225/9)

= 200* 9/225

= 8 seconds

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The correct option is (A).

Answer with explanation:

Time =Distance covered/ speed

In this problem, both the trains are moving so we will find the relative speed of the train. They are moving in the opposite direction, so the relative speed will be sum of their individual speeds.

Relative speed: (50+60) = 110 km/hr

Relative speed in m/s = 110 *5/18 = 275/9

Distance covered is equal to the sum of the length of trains: 140 + 166= 306 meters

Time =306/(275/9)

= 306*9/275= 10 seconds

The correct option is (C).

Answer with explanation:

Time =Distance covered/speed

In this problem, both the trains are in motion so we will find the relative speed of the train. They are moving in the same direction, so the relative speed is equal to the difference of their individual speeds.

Relative Speed: (82-64) = 18 km/hr

Relative Speed in m/s: 18*5/18= 5 m/s

Distance covered is equal to the sum of the length of trains: 120+140 = 260 meters

Time =260/5= 52 seconds

The correct option is (A).

Answer with explanation:

The train and man are moving in opposite direction so the speed of train relative to man is the sum of their individual speeds.

Let the speed of train is X km/hr

Then the relative speed will be: (X + 10) km/hr

In this problem the other way to find the relative speed is to divide the distance covered (length of train) by the time taken by the train to cross the man.

Relative Speed =200/12 =50/3

Relative Speed in Km/hr = 50/3 * 18/5= 60 km/hr

Now, X+10 = 60

X= 60 − 10= 50 km/hr

The correct option is (B).

Answer with explanation:

Let the trains are moving at X m/s and Y m/s respectively.

So, length of the first train: (speed) * (time taken to cross the standing man) = X * 36 seconds= 36X

In a similar way, length of second train: (speed) * (time taken to cross the standing man) = Y * 26 seconds= 26Y

The trains take 30 seconds to cross each other =Total distance covered/Relative speed

Total Distance = sum of the length of trains (36X + 26Y)

Relative Speed = X + Y, as the trains are moving in opposite direction.

Time =Total distance covered/Relative speed

30 =(36x + 26y)/(x+y)

30 X + 30 Y = 36X + 26 Y

30 X − 36X= 26Y − 30Y

-6X=-4Y

x/y=-4/-6=4/6

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