"One year in the 1990s January 1st fell on a Monday. 11 years later, January 1st was also on a Monday. How many times did February 29th occur during those years"?

Sorry but I don't have any working out because I'm completely befuddled by this.

I don't know how to work out if a year started with a Monday or otherwise, does anyone know how?

And I also don't know what's so special about February the 29th? Is it just a normal date and Im being cynical?