UPSC Prelims 2026 · CSAT Paper 2 · Set DMathematicsQ 70 / 80

UPSC Prelims 2026 CSAT Paper 2 — Question 70

Question

X, Y and Z jump forward 4', 6' and 5', respectively. At 8 AM, they all land on mark 199'. How many times will they all land on the same mark (need not be at the same moment) between mark 195' and 1000', if all of them cross mark 1000' by 9 AM?

(a)11
(b)12
(c)13
(d)14

UnlockIAS answer: (d)14

Solution

A common landing mark must be 199 + 60t (since LCM of 4, 6, 5 = 60). For 195 < 199 + 60t ≤ 1000, t = 0 to 13, giving 14 common marks.

UnlockIAS expert key, prepared 24 May 2026 and cross-verified by re-deriving the answer — this is our key, not the official UPSC provisional key (awaited).

Section

Mathematics

Topic Reference

Numeracy — LCM (jumps)

Official UPSC key still awaited

UPSC has announced (PIB Release 2262441, 18 May 2026) that the provisional answer key for CSE Prelims 2026 will be released “soon after Exam”. Until then, use the CSAT score calculator for your qualifying-status estimate, and join the per-question discussion below.

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Official Notification

PIB Release 2262441

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