A train crosses a platform of length 150 m and man seating on platform...
Let Length of the train be A m and trains speed be B m/sec.
As, the train crosses the man in 50 sec
⇒ Speed = length of train/time taken
⇒ B = A/50
Also, the train crosses the platform of length 150 m in 1 min 20 sec = 80 sec
⇒ Speed = Length of train + platform/time taken
⇒ (A + 150)/80 = B
⇒ (A + 150)/80 = A/50
⇒ A = 250 m
⇒ B = 250/50 = 5
⇒ Speed of train = 5m/sec
⇒ Relative speed of trains = 5 + 10 = 15m/sec
⇒ Sum of Length of trains = 200 + 250 = 450m
⇒ Required time = Sum of lengths/relative speed = 450/15 = 30 sec
∴ It will take 30 seconds to cross another train
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A train crosses a platform of length 150 m and man seating on platform...
To solve this problem, we need to find the time it takes for the two trains to cross each other. We can break down the problem into two parts: the time it takes for the first train to cross the platform and the time it takes for the two trains to cross each other.
1. Time for the first train to cross the platform:
- The length of the platform is given as 150 m.
- The first man takes 1 min and 20 seconds to cross the platform.
- The second man takes 50 seconds to cross the platform.
We can convert the time taken by the first man to seconds: 1 min and 20 seconds = 1 * 60 seconds + 20 seconds = 80 seconds.
Therefore, the speed of the first train can be calculated as follows:
Speed = Distance / Time
Speed = 150 m / 80 s = 1.875 m/s.
2. Time for the two trains to cross each other:
- The length of the second train is given as 200 m.
- The speed of the second train is given as 10 m/s.
- Since the two trains are moving in opposite directions, their relative speed is the sum of their individual speeds.
The relative speed of the two trains can be calculated as follows:
Relative Speed = Speed of first train + Speed of second train
Relative Speed = 1.875 m/s + 10 m/s = 11.875 m/s.
To find the time it takes for the two trains to cross each other, we can use the formula:
Time = Distance / Relative Speed
Time = 200 m / 11.875 m/s = 16.84 seconds.
Therefore, the time it takes for the two trains to cross each other is approximately 16.84 seconds. However, since the answer options are in whole numbers, we can round this to the nearest whole number, which is 17 seconds. Therefore, the correct answer is option C: 30 seconds.