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 ✓ UPSC's answer
- (c) 03% decrease
- (d) 02% decrease
Why the answer is (b)
• Let the initial salary be 100, so initial savings are 10 (10% of 100) and initial expenditure is 90.
• The new salary is 112 (100 + 12% increase).
• The new expenditure is 99 (90 + 10% increase).
• The new savings amount is 112 - 99 = 13.
• The change in savings is 13 - 10 = 3, which is a 30% increase over the original savings of 10.
Why the other options are wrong
- (a) 20% increase
- A 20% increase would imply new savings of 12, but the calculated new savings are 13.
- (c) 03% decrease
- Savings increase from 10 to 13, so there is no decrease.
- (d) 02% decrease
- Savings increase from 10 to 13, so there is no decrease.
Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2026, held on 24 May 2026. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.