XAT 2022 — QA & DI Question 17
Read the following scenario and answer the THREE questions that follow.
An examination had ten multiple choice questions; labelled Q1 to Q10 respectively. Each question had four answer options — A, B, C and D — of which one and only one was the correct answer. For each correct answer, the candidate obtained 1 mark. There were no negative marks for wrong answers. The answers chosen by six candidates named Om, Pavan, Qadir, Rakesh, Simranjeet and Tracey to each of the ten questions and the total marks obtained by each of them are shown in the table.
âââââââ
Which of these questions witnessed the least number of the students answering correctly?
Answer & solution
- A
Both Q3 and Q4
Q4
- C
Q5
- D
Q10
- E
Q2
Of the different possibilities are ( 1, 6, 7), (1, 6, 9), (6, 7, 9), (1, 7, 9).
But the cases 6, 7, 9 fails because if he answered all three of them correctly then he must have answered 1 wrongly but since if 1 is answered wrong then all of 1, 6, 7, 9 are answered correctly by Simarjeet when
Simarjeet can answer actually a total of 3 questions only correctly hence this case fails.
Similarly if considered the cases ( 1, 6, 7) and (1, 6, 9) as the questions which were answered correctly. The cases fail because if they are answered correctly we cannot possibly have Pavan answering 5 questions correctly.
Hence the only possibility is he must have answered the questions :
( 1, 7, 9) correctly.
Hence the correct answers are:
âââââââ
Now drawing the table based on the answers marked by them
âââââââ
Simarjeet must have answered 1 question of the Q2, Q4, and Q6 correctly. Qadir must have answered the remaining two of them correctly.
If Simarjeet answered Q4 correctly and Q2, Q6 wrong the answers for Q2, Q4 and Q6 will be: B, B, and D
But if Q2 and Q4 are answered as B then Om must have scored 3 marks instead of2 and hence the case fails.
If Simarjeet answered Q6 correctly and Q2, Q4 wrong the answers for Q2, Q4 and Q6 will be: A, C, and C.
But Pavan cannot score 5 marks.
Hence Simarjeet must have answered Q2 correctly and answers for Q2, Q4, and Q6 will be :
(B, C, D).
âââââââ
Q4 was answered wrong by 5 members.