2014 CSAT, all questions
UPSC Prelims 2014 · CSAT
Question 50: Basic Numeracy
A worker reaches his factory 3 minutes late if his speed from his house to the factory is 5 km/hr. If he walks at a speed of 6 km/hr, then he reaches the factory 7 minutes early. The distance of the factory from his house is
a3 km
b4 km
c5 km
d6 km
AnswerUPSC’s answer is (c).
The two arrival times differ by 3 + 7 = 10 minutes, which is 1/6 hour. The distance d is the same, so d/5 - d/6 = 1/6, giving d/30 = 1/6 and d = 5 km. Check: at 5 km/h the walk takes 60 minutes and at 6 km/h it takes 50, so the 10-minute gap matches.
Why each option is right or wrong
- (a) At 3 km the two walks would differ by 6 minutes, not 10.
- (b) At 4 km the gap would be 8 minutes (48 and 40).
- (c) Right. 5 km gives 60 and 50 minutes, a 10-minute gap.
- (d) At 6 km the gap would be 12 minutes (72 and 60).
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2014, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.