Question

help guys hello if you don't know the answer please don't answer​

Answer 1

1. The first approach is wrong because we cant fill the pool in the time of sum of each pipes to fill. because we know one pipe can even fill the the pool in 12 hours. So the another pipe must help to contract the time to fill the pool
2. The second approach is wrong because, The difference of each pipes that can fill the pool cant be taken as a time taken to fill the pool. Because both the first pipe can fill the tank the in 12 hours so the second pipe make the time decrease but not by difference.
3. The third approach is wrong because we cant fill the tank by finding its average . But we can have the LCM of both the pipes that can fill the tank in particular hour as a equivalent value as 1