A swimming pool has four taps. The first can fill the entire pool with water in two days, the second in three days, the third in four days, and the last one can fill the pool in 6 hours. How long will it take to fill the pool using all 4 taps together?
Answer
It will take 4 hours 43 mins 16.72 seconds to fill the pool.
In one hour:
1st tap fills 1/48 of the pool
2nd tap fills 1/72 of the pool
3rd tap fills 1/96 of the pool
4th tap fills 1/6 of the pool
This adds up to 61/288 (1/48 + 1/72 + 1/96 + 1/6) for 1 hour. To fill the pool, it will take 288/61 hours.