1995 General Studies, all questions
UPSC Prelims 1995 · General Studies
Question 140: Basic Numeracy
A thief running at 8 km/hr is chased by a policeman whose speed is 10 km/hr. If the thief is 100 metres ahead of the policeman, then the time required for the policeman to catch the thief will be
a2 minutes
b6 minutes
c10 minutes
d3 minutes
AnswerThe answer is (d).
The policeman gains on the thief at the difference of their speeds: 10 - 8 = 2 km/h. The gap is 100 m = 0.1 km. Time to catch = 0.1 / 2 = 0.05 hour = 3 minutes. Remember: closing time equals the gap divided by the relative speed.
Why each option is right or wrong
- (a) 2 minutes is too short for a 2 km/h closing speed.
- (b) 6 minutes is twice the time.
- (c) 10 minutes is far too long.
- (d) Right: 0.1 / 2 hours = 3 minutes.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 1995, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.