Final answer:
It will take the man 125 seconds to cross a 50-meter pool at a speed of 0.4 m/s, corresponding to option (a).
Step-by-step explanation:
To determine how long it will take a man to swim across a pool that is 50 meters in length at a speed of 0.4 m/s, we use the formula for time, which is time = distance / speed. So, the time taken (t) can be calculated as follows:
t = 50 m / 0.4 m/s = 125 seconds.
Therefore, it will take the man 125 seconds to cross the pool, which corresponds to option (a).
This means it will take the man 125 seconds to complete the swim. Accurate time calculations are crucial in various activities, especially in sports and physical exercises, where understanding the duration of actions contributes to effective planning and performance assessment. The correct answer is indeed option (a).