1998 General Studies, all questions
UPSC Prelims 1998 · General Studies
Question 145: Logical Reasoning and Mental Ability
An accurate clock shows the time as 3 : 00. After the hour hand has moved 135°, the time would be
a7 : 30
b6 : 30
c8 : 00
d9 : 30
AnswerThe answer is (a).
The hour hand moves 30 degrees in an hour, so 0.5 degree a minute. A movement of 135 degrees takes 135 / 30 = 4.5 hours, that is 4 hours 30 minutes. From 3:00 this gives 7:30. Check: in 4.5 hours the hour hand has moved 4.5 x 30 = 135 degrees, and at 7:30 it is halfway between 7 and 8.
Why each option is right or wrong
- (a) Right: 4.5 hours after 3:00 is 7:30.
- (b) 6:30 is only 3.5 hours later, 105 degrees.
- (c) 8:00 is 5 hours later, 150 degrees.
- (d) 9:30 is 6.5 hours later, 195 degrees.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 1998, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.