UPSC Prelims 2026 · CSAT
Question 50: Basic Numeracy
X travels 6 km on a bicycle with average speeds of 5 km per hour, 10 km per hour and 4 km per hour during the first 1 km, the next 2 km and the remaining 3 km, respectively. Y travels the same distances with average speeds of 4 km per hour, 10 km per hour and 5 km per hour, respectively. How many minutes early will Y complete the journey if both X and Y start at the same time?
AnswerUPSC’s answer is (d).
Use time = distance ÷ speed. X: 1/5 h + 2/10 h + 3/4 h = 12 + 12 + 45 = 69 minutes. Y: 1/4 h + 2/10 h + 3/5 h = 15 + 12 + 36 = 63 minutes. Both ride the same 6 km, so Y finishes 69 − 63 = 6 minutes earlier.
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 UPSC’s provisional key; the final key could change it.
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) Wrong: the gap is 6 minutes, not 3.
- (b) Wrong: the gap is 6 minutes, not 4.
- (c) Wrong: the gap is 6 minutes, not 5.
- (d) Right: 69 − 63 = 6 minutes.
Only the provisional key (27 May 2026) was found; the final key replaces it when found.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2026, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.