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. The official UPSC provisional key has been released.

Section

Mathematics

Topic Reference

Numeracy — Percentages

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

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