UPSC Prelims 1997 · General Studies
Question 145: Basic Numeracy
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 and one person can speak all the three languages, then how many persons are there in the group?
AnswerThe answer is (c).
Add up the language-speakers: 6 + 15 + 6 = 27. Two persons speak exactly two languages, counted twice each (4), and one person speaks all three, counted three times (3). That accounts for 7 of the 27, leaving 20 persons who speak only one language. Total persons = 20 + 2 + 1 = 23.
How you could have got this
No shortcut here: in a “how many” question, ruling out options doesn’t help. Every statement has to be judged.
This follows an unofficial answer: UPSC has not published its key for this year, and if that answer is wrong, so is this path.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) 21 does not fit the count 20 + 2 + 1.
- (b) 22 does not fit the count 20 + 2 + 1.
- (c) Right: 20 + 2 + 1 = 23.
- (d) 24 comes from counting the all-three speaker as one of the two multi-language persons.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 1997, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.