Question 10
Cecilia, Dina, Elena, and Fiona are cousins with different ages who live in the same house. When a new neighbor asked them who is the oldest, they answered: Cecilia: I am the eldest. Dina: I am not the youngest. Elena: I am neither the eldest nor the youngest. Fiona: I am the youngest. Given that one of them is not telling the truth, who is the oldest of the four cousins?