CAT 1992 — VARC Question 43
Kya –Kya is an obscure island which is inhabited by two types of people: the ‘Yes’ type and the ‘No’ type. Native of type ‘Yes’ ask only questions the right answer to which is ‘Yes’ while those of type ‘No’ ask only questions the right answer to which is ‘No’. For example. The ‘Yes’ type will ask questions like “Is 2 plus 2 equal to 4?” while the ‘No’ type will ask questions like “Is 2 plus 2 equal to five?” The following questions are based on your visit to the island of Kya – Kya.
Each of three friends knows whether the other two have passed or failed in an examination, but does not know his own result. The teacher comes and says, “At least one has failed”. If all three still does not know their own results which of the following is true?
Answer & solution
- A
One student has failed.
- B
Two students have failed.
Two or more students have failed.
- D
All three have failed.
If only one had failed than the person who had failed would have known that the other two had passed so he had failed. But the question states that no one still knows his own result.