UPSC Prelims 2000 · General Studies
Question 130: Logical Reasoning and Mental Ability
An accurate clock shows 8 o’clock in the morning. Through how many degrees will the hour hand rotate when the clock shows 2 o’clock in the afternoon?
AnswerThe answer is (d).
The hour hand covers 360 degrees in 12 hours, that is 30 degrees an hour. From 8 in the morning to 2 in the afternoon is 6 hours, so the hand turns 6 x 30 = 180 degrees. The minute hand, by contrast, turns 360 degrees every hour, so it plays no part in this answer.
How you could have got this
No shortcut here: in a “how many” question, ruling out options doesn’t help. Every statement has to be judged.
This follows an unofficial answer: UPSC has not published its key for this year, and if that answer is wrong, so is this path.
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) 150 degrees is only 5 hours of movement.
- (b) 144 degrees is not a whole number of hours at 30 degrees each.
- (c) 168 degrees is not a whole number of hours at 30 degrees each.
- (d) Right: 6 hours x 30 degrees = 180 degrees.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2000, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.