Practice UPSC CSAT previous year questions from 2011–2026 classified underSet Theory. Review the original question, four options, correct answer and explanation for every PYQ.
5 questions • 2011–2026
In a town, 45% population read magazine A, 55% read magazine B, 40% read magazine C, 30% read magazines A and B, 15% read magazines B and C, 25% read magazines A and C; and 10% read all the three magazines. What percentage do not read any magazine?
Using inclusion–exclusion, the percentage reading at least one is 45+55+40−30−15−25+10=80%; hence 20% read none.
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?
The total of language memberships is 6+15+6=27. A person speaking all three contributes 3 and each of the two bilingual persons contributes 2, so total people = 27−2−2=23.
The number of persons who read magazine X only is thrice the number of persons who read magazine Y. The number of persons who read magazine Y only is thrice the number of persons who read magazine X. Then, which of the following conclusions can be drawn? 1. The number of persons who read both the magazines is twice the number of persons who read only magazine X. 2. The total number of persons who read either one magazine or both the magazines is twice the number of persons who read both the magazines. Select the correct answer using the code given below:
The uploaded Series-A key marks this item X (dropped). It is therefore not scored and no official answer should be substituted.
Ten new TV shows started in January—5 sitcoms, 3 drama and 2 news magazines. By April, only seven of the new shows were still on, five of them being sitcoms. Based on the above information, four conclusions, as given below, have been made. Which one of these logically follows from the information given above?
Seven shows remain, five of them sitcoms, so only two non-sitcoms remain from five non-sitcoms. Therefore at least one of the three drama shows must have been discontinued.
In the above figure, circle P represents hardworking people, circle Q represents intelligent people, circle R represents truthful people, and circle S represents honest people. Which region represents the people who are intelligent, honest and truthful but not hardworking?
The required region must lie inside Q, R and S but outside P. In the diagram that region is 6.
Attempt questions one by one with UPSC-style marking and immediate explanations.