UPSC Prelims 2026 · CSAT Paper 2 · Set DMathematicsQ 40 / 80

UPSC Prelims 2026 CSAT Paper 2 — Question 40

Question

If x and y are two digits and the number 4x5y790 is divisible by 11, then what is the remainder, if x + y is divided by 11?

(a)1
(b)3
(c)5
(d)7

UnlockIAS answer: (d)7

Solution

Alternating digit sum = 4 − x + 5 − y + 7 − 9 + 0 = 7 − (x + y), which must be a multiple of 11, so x + y = 7 (or 18). In either case (x + y) mod 11 = 7.

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 — Divisibility by 11

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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