In an examination, A has scored 20 marks more than B. If B has scored 5% less marks than A, how much has B scored ?
- (a) 360
- (b) 380 ✓ UPSC's answer
- (c) 400
- (d) 420
Why the answer is (b)
• A scored 20 marks more than B, and B scored 5% less than A, so the 20-mark gap is 5% of A's score.
• A = 20 ÷ 0·05 = 400, so B = 400 − 20 = 380, option (b).
Why the other options are wrong
- (a) 360
- If B scored 360, A would score 380, and 20 is about 5·3% of 380, not 5%.
- (c) 400
- 400 is A's score, not B's.
- (d) 420
- If B scored 420, A would score 440, and 20 is about 4·5% of 440, not 5%.
Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2019, held on 2 June 2019. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.