UPSC Prelims 2022 · CSAT
Question 68: Logical Reasoning and Mental Ability
Consider the following statements :
- 1.Between 3:16 p.m. and 3:17 p.m., both hour hand and minute hand coincide.
- 2.Between 4:58 p.m. and 4:59 p.m., both minute hand and second hand coincide.
Which of the above statements is/are correct?
AnswerUPSC’s answer is (c).
Statement 1: at 3:00 the hour hand is at 90°. The minute hand gains 5.5° per minute on it, so it catches up after 90 ÷ 5.5 = 16 4/11 minutes, about 3:16:22, inside the 3:16 to 3:17 window. Statement 2: at 4:58 the minute hand is at 348°, and the second hand gains 5.9° per second on it, so they meet after 348 ÷ 5.9 ≈ 58.98 seconds, about 4:58:59, inside the window. Both are correct.
- 1. The hands coincide at 16 4/11 minutes past 3.
- 2. Minute and second hands meet about 59 seconds after 4:58.
How you could have got this
- If you were sure statement 1 is correct, (b) and (d) go: each of them leaves 1 out.
What you needed to know: The hands coincide at 16 4/11 minutes past 3.
- Then, if you were sure statement 2 is correct, (a) goes: it leaves 2 out.
What you needed to know: Minute and second hands meet about 59 seconds after 4:58.
Only (c) is left. This one needs every statement.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Wrong: statement 2 is also correct.
- (b) Wrong: statement 1 is also correct.
- (c) Correct: both meetings occur within the stated minutes.
- (d) Wrong: both statements hold.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2022, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.