2017 CSAT, all questions
UPSC Prelims 2017 · CSAT
Question 54: Basic Numeracy
P works thrice as fast as Q, whereas P and Q together can work four times as fast as R. If P, Q and R together work on a job, in what ratio should they share the earnings?
a3 : 1 : 1
b3 : 2 : 4
c4 : 3 : 4
d3 : 1 : 4
AnswerUPSC’s answer is (a).
P = 3Q, so P + Q = 4Q. Given P + Q = 4R, we get 4Q = 4R, so R = Q. Work rates are therefore P : Q : R = 3 : 1 : 1. Working together for the same time, each is paid in proportion to the work done, so the earnings are shared 3 : 1 : 1. Convert every statement into an equation in one variable before comparing.
Why each option is right or wrong
- (a) Correct: the rates are 3Q, Q and Q.
- (b) P is not three times Q here (3 : 2).
- (c) P is not three times Q here (4 : 3).
- (d) P and Q together equal R here, not four times R.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2017, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.