?8. Which day ?

Sam lies a lot:

• He speaks the truth only on one particular day in a week.
• One day he said " I lie on Mondays and Tuesdays."
• The next day he said " Today is either Thursday or Saturday or Sunday."
• The next day he said " I lie on Wednesdays and Fridays."

Which day of the week does Sam tells the truth ?

Answer: Tuesday  
           Simply make cases when each of the 3 days mentioned is the lie day and the case  when    none of them is the lie day and then use elimination.