Truth or Liar
John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.
I called their home number and one of them picked up.
I asked. ‘Does John lie?’ The person replied with a yes.
Whom did I talk with, John or Jacob?
We have two possibilities:
(1) John is the liar and Jacob says the truth OR
(2) Jacob is the liar and John says the truth.
In both the cases, we have two possible outcomes of the call:
(a) John attended the call OR
(b) Jacob attended it.
Assuming (1) was correct, i.e., John is the liar:
If (a) were correct, i.e., John attended the call, then he would have said ‘no’ because he’s the liar, and hence wouldn’t have admitted it. But the person who attended the call said ‘Yes’. So, it can’t be John who picked the call. i.e., it must be Jacob.
Now, if we assume that (2) was correct, i.e., Jacob is the lair. Then:
If (a) were correct, i.e., John attended the call, he would have told the truth – that he does not lie. But the person said ‘Yes’. So, it can’t be John who attended the call. It must be Jacob,
Thus, in either case, it must be Jacob who attended the call.
More puzzles to try-
What is the logic behind these ?3 + 3 = 3 5 + 4 = 4 1 + 0 = 3 2 + 3 = 4 ...Read More »
Defective stack of coins puzzleThere are 10 stacks of 10 coins each. Each coin weights 10 gms. However, one stack of coins is defective ...Read More »
Which clock works best?Which clock works best? The one that loses a minute a day or the one that doesn’t work at all?Read More »
(Advanced) Cheryl’s Birthday PuzzlePaul, Sam and Dean are assigned the task of figuring out two numbers. They get the following information: Both numbers ...Read More »
Five greedy pirates and gold coin distribution PuzzleFive puzzleFry ship’s pirates have obtained 100 gold coins and have to divide up the loot. The pirates are all ...Read More »
Magical flowers!!A devotee goes to three temples, temple1, temple2 and temple3 one after the other. In front of each temple, there ...Read More »
Tuesday, Thursday what are other two days staring with T?Four days are there which start with the letter ‘T‘. I can remember only two of them as “Tuesday , Thursday”. ...Read More »
How could only 3 apples leftTwo fathers took their sons to a fruit stall. Each man and son bought an apple, But when they returned ...Read More »
How Many Eggs ?A farmer is taking her eggs to the market in a cart, but she hits a pothole, which knocks over ...Read More »
HARD MATHS – How much faster is one train from other PuzzleTwo trains starting at same time, one from Bangalore to Mysore and other in opposite direction arrive at their destination ...Read More »
Most Analytical GOOGLE INTERVIEW Question RevealedLet it be simple and as direct as possible. Interviewer : Tell me how much time (in days) and money would ...Read More »
Lateral thinking sequence PuzzleSolve this logic sequence puzzle by the correct digit- 8080 = 6 1357 = 0 2022 = 1 1999 = ...Read More »
How did he know?A man leaves his house in the morning to go to office and kisses his wife. In the evening on ...Read More »
Pizza Cost Math Brain TeaserJasmine, Thibault, and Noah were having a night out and decided to order a pizza for $10. It turned out ...Read More »
Which letter replaces the question markWhich letter replaces the question markRead More »
Which room is safest puzzleA murderer is condemned to death. He has to choose between three rooms. The first is full of raging fires, ...Read More »
Richie’s Number SystemRichie established a very strange number system. According to her claim for different combination of 0 and 2 you will ...Read More »
Srabon wanted to passThe result of math class test came out. Fariha’s mark was an even number. Srabon got a prime!! Nabila got ...Read More »
Become Normal!!Robi is a very serious student. On the first day of this year his seriousness for study was 1 hour. ...Read More »
Sakib Knows The Number!Ragib: I got digits of a 2 digit number Sakib: Is it an odd? Ragib: Yes. Moreover, the sum of ...Read More »