UPSC Prelims 2026 · CSAT Paper 2 · Set DMathematicsQ 23 / 80

UPSC Prelims 2026 CSAT Paper 2 — Question 23

Question

A person saves 10% of his salary every month. If his salary increases by 12% and the expenditure increases by 10%, then what will be the change in his saving per month?

(a)20% increase
(b)30% increase
(c)03% decrease
(d)02% decrease

UnlockIAS answer: (b)30% increase

Solution

Let salary = S, saving = 0.10S, expenditure = 0.90S. New saving = 1.12S − 1.10 × 0.90S = 1.12S − 0.99S = 0.13S. Increase = (0.13 − 0.10)/0.10 = 30%.

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 — Percentages

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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