2016 CSAT, all questions
UPSC Prelims 2016 · CSAT
Question 74: Logical Reasoning and Mental Ability
In a class of 60 students, where the number of girls is twice that of boys, Kamal, a boy, ranked seventeenth from the top. If there are 9 girls ahead of Kamal, the number of boys in rank after him is :
a13
b12
c7
d3
AnswerUPSC’s answer is (b).
Girls are twice boys in a class of 60, so boys = 20 and girls = 40. Kamal is 17th from the top with 9 girls ahead, so the 16 ahead of him are 9 girls and 7 boys. He is therefore the 8th boy in rank, leaving 20 - 8 = 12 boys behind him.
Why each option is right or wrong
- (a) 13 would make Kamal the 7th boy, but 7 boys are ahead of him.
- (b) Right: 20 boys minus 8 gives 12.
- (c) 7 is the number of boys ahead of Kamal.
- (d) 3 does not follow from the counts.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2016, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.