UPSC Prelims 2009 · General Studies
Question 102: Basic Numeracy
In an examination, there are three subjects A, B and C. A student has to pass in each subject. 20% students failed in A, 22% students failed in B and 16% failed in C. The total number of students passing the whole examination lies between
AnswerThe answer is (b).
Failures are 20%, 22% and 16%. The share failing at least one subject is smallest when all failures overlap with the biggest group, 22%, and largest when no student fails two subjects, 20 + 22 + 16 = 58%. So the share passing everything lies between 100 - 58 = 42% and 100 - 22 = 78%.
Why each option is right or wrong
- (a) 84% is not reachable, as at least 22% fail.
- (b) Right: between 42% and 78%.
- (c) 58% is not the minimum pass rate.
- (d) 58% and 84% do not follow from the minimum and maximum failure rates.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2009, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.