A man swim at 5 km per hour velocity in still water He takes 75 minute...
Let the distance be x
Relative speed when travelling upstream = 5 - 1 = 4 kmph
Relative speed when travelling downstream = 5 + 1 = 6 kmph
Time taken = 75 minutes = 1.25 hours
So, x/4 + x/6 = 1.25
So, x = 3 kms
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A man swim at 5 km per hour velocity in still water He takes 75 minute...
To solve this problem, we can use the concept of relative velocity. Relative velocity is the velocity of an object with respect to another object.
Let's assume that the distance between positions A and B is x km.
1. Find the time taken to swim from A to B:
The man's velocity in still water is 5 km/h, and the river's velocity is 1 km/h. Therefore, the man's effective velocity while swimming from position A to position B is (5 - 1) = 4 km/h.
We know that time = distance / velocity.
So, the time taken to swim from A to B is x / 4 hours.
2. Find the time taken to swim from B to A:
The man's velocity in still water is 5 km/h, and the river's velocity is 1 km/h in the opposite direction. Therefore, the man's effective velocity while swimming from position B to position A is (5 + 1) = 6 km/h.
Again, using the formula time = distance / velocity, the time taken to swim from B to A is x / 6 hours.
3. Total time taken:
According to the problem, the total time taken to swim from position A to position B and back is 75 minutes, which is equivalent to 75/60 = 1.25 hours.
So, the total time taken is:
x / 4 + x / 6 = 1.25
4. Solve the equation:
To solve the equation, we can multiply both sides by 12 to eliminate the denominators:
3x + 2x = 15
5x = 15
x = 3 km
Therefore, the distance between positions A and B is 3 km.
Hence, the correct answer is option D) 3 km.
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