2019 CSAT, all questions
UPSC Prelims 2019 · CSAT
Question 52: Basic Numeracy
In a group of 15 people; 7 can read French, 8 can read English while 3 of them can read neither of these two languages. The number of people who can read exactly one language is
a10
b9
c5
d4
AnswerUPSC’s answer is (b).
Of 15 people, 3 read neither, so 12 read at least one language. French plus English readers = 7 + 8 = 15, which counts those who read both twice, so both = 15 - 12 = 3. Exactly one language = 12 - 3 = 9. Equivalently, (7 - 3) + (8 - 3) = 4 + 5 = 9.
Why each option is right or wrong
- (a) Wrong: 10 does not fit an overlap of 3.
- (b) Right: (7 - 3) + (8 - 3) = 9.
- (c) Wrong: 5 is the number who read only English.
- (d) Wrong: 4 is the number who read only French.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2019, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.