In a test, a candidate attempted only 8 questions and secured 50% marks in each of the questions. If he obtained a total of 40% in the test and all questions in the test carried equal marks, how many questions were there in the test ?
- (a) 8
- (b) 10 ✓ UPSC's answer
- (c) 15
- (d) 16
Why the answer is (b)
• Let the total number of questions in the test be $N$.
• Since all questions carry equal marks, let the marks for each question be 1 unit.
• The candidate attempted 8 questions and scored 50% in each, so the total marks obtained = $8 \times 0.5 = 4$ units.
• The candidate obtained a total of 40% in the test, which means the total marks obtained is 40% of the maximum possible marks ($N$).
• Therefore, $4 = 0.40 \times N$.
• Solving for $N$, we get $N = 4 / 0.40 = 10$.
• Thus, there were 10 questions in the test, which corresponds to option (b).
Why the other options are wrong
- (a) 8
- If there were 8 questions, the candidate would have scored 100% in the test, not 40%.
- (c) 15
- If there were 15 questions, the candidate's score of 4 units would represent approximately 26.67%, not 40%.
- (d) 16
- If there were 16 questions, the candidate's score of 4 units would represent 25%, not 40%.
Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2015, held on 23 August 2015. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.