Vikram and Muthu ask their friend when is her birthday. She does not give a straight forward answer, but gives some hints.
She gives them the following 10 dates to pick her birthday.
May: 15, 16, 19
June: 17, 18
July: 14, 16
August: 14, 15, 17
Then she discloses correct month to Vikram and the correct date to Muthu.
Asks Vikram to guess the right birthday. He says sorry I can’t, but I am sure even Muthu won’t be able to guess it right.
Now Muthu says, I was a bit confused but with Vikram’s statement, I know what is her birthday.
Now Vikram says if that is the case, I also know what is it.
Both guessed it right. Use simple logic to guess the right birthday.