In a group of persons travelling in a bus, 6 persons can speak Tamil, 15 can speak Hindi and 6 can speak Gujarati. In that group none can speak any other language. If 2 persons in the group can speak two languages only and one person can speak all the three languages, then how many persons are there in the group ?
- (a) 21
- (b) 22
- (c) 23 ✓ UPSC's answer
- (d) 24
Why the answer is (c)
• Add the language counts: 6 + 15 + 6 = 27.
• A person who speaks exactly two languages is counted twice, and the person who speaks all three is counted three times.
• Extra counts = 2 persons × 1 extra + 1 person × 2 extra = 4.
• Number of persons = 27 − 4 = 23.
• Hence option (c).
Why the other options are wrong
- (a) 21
- 21 subtracts too much: 27 − 6 treats both bilingual speakers as counted three times.
- (b) 22
- 22 subtracts 5 instead of 4 extra counts.
- (d) 24
- 24 subtracts only 3, missing one of the extra counts.
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.