KöMaL 2016 K517

In Normalia, there is a city in which the people called ,,truetellers'' always tell the truth. Those who are not truetellers will tell the truth one day, and then lie on the following day, then also tell the truth, and so on. The last names of Andrew, Barbara, and Cecilia are Small, Large and Long, in some order. Determine the last name of each of them, given their statements below: on Monday Andrew: Barbara is not telling the truth. Barbara: I am not a trueteller. Cecilia: There is a trueteller among us. on Tuesday Andrew: Cecilia told the truth yesterday. Barbara: Andrew's last name is either Large or Small. Cecilia: Barbara's last name is not Small.