Hello, harish21!

Let = total number of fish.Three fisherman come back from a day of fishing and put their fish together and go to bed.

The 1st one wakes up, goes to the pile of fish, throws one away and takes a 3rd and leaves.

The 2nd one does the same. The last one does the same as well.

What is the minimum number of fish that this can work with?

The 1st discards one fish and take a third of the remainder.

Then must be of the form: .

. . .[1]

He discards one fish . . . fish left.

He take a third of the fish ( fish) and leaves.

There are fish left.

The 2nd discards one fish and takes a third of the remainder.

Then must be of the form

. . .[2]

He discards one fish . . . fish left.

He take third of the fish ( fish) and leaves.

There are fish left.

The 3rd discards one fish and takes a third of the remainder.

Then must be of the form

. . .[3]

Substitute [3] into [2]: . .[4]

Substitute [4] into [1]: .

We have: .

Hence: .

Since is an integer, must be divisible by 4.

The first time this happens is when

Therefore: .