XAT 2015 — QA & DI Question 20
In an examination, two types of questions are asked: one mark questions and two marks questions. For each wrong answer, of one mark question, the deduction is 1/4 of a mark and for each wrong answer, of two marks question, the deduction is 1/3 of a mark. Moreover, 1/2 of a mark is deducted for any unanswered question. The question paper has 10 one mark questions and 10 two marks questions. In the examination, students got all possible marks between 25 and 30 and every student had different marks. What would be the rank of a student, who scores a total of 27.5 marks?
Answer & solution
5
- B
6
- C
7
- D
8
- E
None of theabove
Maximum marks = 30
Marks scored if exactly 29 questions were answered correctly.
Case (1): One question is incorrectly answered.
Case (1a): A question of 1 mark is answered incorrectly.
Total marks = 30 – 1 – 0.25 = 28.75
Case (1b): A question of 2 marks is answered incorrectly.
Total marks = 30 – 2 – 0.33 = 27.67
Case (2): One question is not answered.
Case (2a): A question of 1 mark is not answered.
Total marks = 30 – 1 – 0.5 = 28.5
Case (2b): A question of 2 marks is not answered.
Total marks = 30 – 2 – 0.5 = 27.5
If these marks are arranged in descending order, (27.5) comes in the fifth place.
i.e., the rank of a student, who scores a total of 27.5 marks, would be 5.
Hence, option (a).