UPSC Prelims 2017 · CSAT
Question 60: Logical Reasoning and Mental Ability
In a certain code, ‘256’ means ‘red colour chalk’, ‘589’ means ‘green colour flower’ and ‘254’ means ‘white colour chalk’. The digit in the code that indicates ‘white’ is
AnswerUPSC’s answer is (b).
Compare the codes. The word colour appears in all three messages, and digit 5 is the only digit in all three codes, so 5 means colour. Chalk is in 256 and 254, whose common digits are 2 and 5; with 5 taken, 2 means chalk. In 254 the remaining digit, 4, must mean white. Find the word common to all messages first, then the digit common to all codes.
Why each option is right or wrong
- (a) 2 stands for chalk.
- (b) Correct: with colour = 5 and chalk = 2, white = 4.
- (c) 5 stands for colour.
- (d) 8 appears only in the green flower code, not in white's.
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.