UPSC Prelims 2007 · General Studies
Question 147: Basic Numeracy
Amit starts from a point A, walks to another point B and then returns from B to A by his car, taking a total time of 6 hours 45 minutes. If he had driven both ways in his car, he would have taken 2 hours less. How long would it take for him to walk both ways?
AnswerThe answer is (d).
Let walking one way take w and driving one way take d. Walking one way and driving back: w + d = 6 h 45 min. Driving both ways: 2d = 6 h 45 min - 2 h = 4 h 45 min, so d = 2 h 22.5 min. Then w = 6 h 45 min - 2 h 22.5 min = 4 h 22.5 min, and walking both ways takes 2w = 8 h 45 min.
Why each option is right or wrong
- (a) 7 h 45 min is too short; walking both ways takes 8 h 45 min.
- (b) 8 h 15 min is too short; the answer is 8 h 45 min.
- (c) 8 h 30 min is too short; the answer is 8 h 45 min.
- (d) Correct: 2 x 4 h 22.5 min = 8 h 45 min.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2007, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.