Philip says truth only one day in a week.
Hint 1: Days are Sun, Mon and so on.
Hint 2: One day he says “I lie on Mon and Tue”.
Hint 3: Next day he says “Today is either Thu, Sat or Sun”.
Hint 4: next day he says “I lie on Wed and Fri”.
On which day he says the truth?
How to get 10 from 9
How to get 10 from 9
The days he speaks above are A,B,C. If he lies on A, then one of Monday and Tuesday are the days he speaks the truth. Similarly, if he lies on C, then one of Wednesday or Friday is the day he speaks the truth. This means that he can’t be lying on both A and C. But since he’s lying on *one* of A and C, the day of truth is Monday, Tuesday, Wednesday, or Friday.
This also means he’s lying on B, so B is not Thursday, Saturday, or Sunday.
So A isn’t Wednesday, Friday, or Saturday.
C isn’t Friday, Sunday, or Monday.
Also also, if A is Monday, he can’t be telling the truth on Monday (he can’t be telling the truth and say “I’m lying today”). Same idea for Tuesday, Wednesday, and Friday. So if A is Monday or Tuesday, C is true. If C is Wednesday or Friday, A is true. (But C can’t be Friday anyway.)
If A is Monday, C is Wednesday. Both have to be lies. A isn’t Monday.
If A is Tuesday, C is Thursday. Both have to be lies. A isn’t Tuesday.
Putting all of this together:
A can only be Thursday or Sunday. Both of these are days that he has to be lying, so C is true. C is Saturday or Tuesday. Saturday is also a lying day, so C is Tuesday.
Sunday: I lie on Monday and Tuesday (lie – he tells the truth on Tuesday)
Monday: Today is Thursday, Saturday, or Sunday (lie)
Tuesday: I lie on Wednesday and Friday (true)
Pradeep Nanda says
1.sunday he told i will lie on mon and tue
so monday and tuesday he will definitly lie.
so next day will be monday
2. monday he says “Today is either Thu, Sat or Sun” (monday he tell lie things)
3.Tuesday he says “I lie on Wed and Fri”.(this is also a lie sentence)
so answer is sunday.
Sourabh Deoghare says
Yes, thurday is right answer
Ans is thursday is the day wen he speaks trurth
yes…i got same answer 🙂