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. The official UPSC provisional key has been released.

Section

Mathematics

Topic Reference

Numeracy — Digit counting

Official UPSC Provisional Key Released

The official provisional answer key for CSE Prelims 2026 has been released. Compare your answers with the official key using our CSAT score calculator, and file objections via the QPRep portal before 6:00 PM on 31 May 2026.

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Official Notification

PIB Release 2262441

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