CAT 2003 Slot 2 — DILR Question 13
Answer the following question based on the information given below.
Recently, the answers of a test held nationwide were leaked to a group of unscrupulous people. The investigative agency has arrested the mastermind and nine other people A, B, C, D, E, F, G, H and I in this matter. Interrogating them, the following facts have been obtained regarding their operation. Initially the mastermind obtains the correct answer-key. All the others create their answer-key from one or two people who already possess the same. These people are called his/her “sources”. If the person has two sources, then he/she compares the answer-keys obtained from both sources. If the key to a question from both sources is identical, it is copied, otherwise it is left blank. If the person has only one source, he/she copies the source’s answers into his/her copy. Finally, each person compulsorily replaces one of the answers (not a blank one) with a wrong answer in his/her answer key.
The paper contained 200 questions; so the investigative agency has ruled out the possibility of two or more of them introducing wrong answers to the same question. The investigative agency has a copy of the correct answer key and has tabulated the following data. These data represent question numbers.
âââââââ
Which of the following statements is true?
Answer & solution
- A
C introduced the wrong answer to question 27.
- B
E introduced the wrong answer to question 46.
F introduced the wrong answer to question 14
- D
H introduced the wrong answer to question 46
A, D and G each one has only one wrong answer and no blank answers.
∴ They must have obtained the key from the mastermind directly.
∴ A introduced 46 as the wrong answer, D introduced 17 as the wrong answer and G introduced 25 as the wrong answer.
H and E must have obtained the key from A as they got 46 as the wrong answer.
∴ H further introduced 92 as the wrong answer and E introduced 90 as the wrong answer.
F must have obtained the key from H and E and found that answers 92 and 90 did not match. He left these blank and introduced 14 as the wrong answer in addition to 46 (which was the same answer though wrong) for H and E.
I must have obtained the key from D and E. Answers 17, 46, 90 didn’t match and he left these as blank. He also introduced 27 as the wrong answer.
C must have obtained the key from I and introduced 56 as the wrong answer.
B must have obtained the key from E and G. Answers 25, 46, 90 didn’t match and he left these blank. He also marked 96 as the wrong answer.
∴ Combining all the above diagrams we get:
From the flowchart we get that, statement 3 is the only true statement.
Hence, option (c).