It is known that Andrew's wedding is on one of the following 10 dates:

August 15, August 16, August 19,

September 17, September 18,

October 14, October 16,

November 14, November 15, November 17.

Andrew tells Jacob and Ben separately the month and the day of his wedding, respectively. Then the following conversation takes place

Jacob: I don't know when Andrew's wedding is, but I know that Ben doesn't know either.

Ben: At first, I didn't know when Andrew's wedding is, but I know now.

Jacob: Then I also know when Andrew's wedding is.

So, when is Andrew's wedding?

Tip: what are your givens? Go through the problem line by line​