Jim is so happy after finding three solutions to a problem, then he texts Bob this :
Bob, I have found 3 solutions for your problem. I do not know whether these three are the only solutions or not, but I am sure there must be less than 15 solutions.
Bob then replies:
Thank you Jim, your solution works perfectly.
Addition to make the puzzle clear :
2 Days later, Jim texts Bob.
I have found all the solutions, it has exactly 11 solutions,
but I hope you find the other solutions yourself
What are they trying to solve ?