UPSC Prelims 2026 · CSAT Paper 2 · Set DMathematicsQ 29 / 80

UPSC Prelims 2026 CSAT Paper 2 — Question 29

Question

How many times does 5 appear in all two-digit positive integers?

(a)18
(b)19
(c)20
(d)21

UnlockIAS answer: (b)19

Solution

As the units digit: 15, 25, …, 95 → 9 times. As the tens digit: 50–59 → 10 times. Total = 9 + 10 = 19.

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 — Digit counting

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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