SSC CGL 2024 Tier-I · 9 September 2024, Shift 2 · Quantitative Aptitude · Question 15 of 100

Text as printed on a candidate's response sheet for this shift; answer per SSC's tentative key as marked on that sheet. Solution last reviewed 5 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. The questions and options here are reproduced as printed on a candidate's own response sheet for this shift — the Commission's text, unchanged. Each answer is SSC's tentative key as marked on that sheet; SSC allowed challenges to it and never publishes a final key. The solutions are written by UnlockIAS.

A person earns ₹16,000 per month and spends 80% of his income and saves the remaining amount. If his income increases by 20% and expenditure by 10%, find the percentage of increase in his savings.

(a)90%
(b)120%
(c)140%
(d)60%

Answer

Why

Correct — D. Get the rupee figures first, then compare.

Income = ₹16,000; spends 80% = ₹12,800
Old savings = 16,000 − 12,800 = ₹3,200

New income = 16,000 × 1.2 = ₹19,200
New expenditure = 12,800 × 1.1 = ₹14,080
New savings = 19,200 − 14,080 = ₹5,120

Rise = 5,120 − 3,200 = ₹1,920
1,920 ÷ 3,200 = 0.6 = 60% → option (d).

Why the others are wrong

(a)
90% — A 90% rise means savings of ₹6,080, which forces expenditure to ₹13,120 — a rise of just 2.5%, not the stated 10%. Savings can only climb by ₹3,200 − ₹1,280 = ₹1,920.
(b)
120% — 120% of ₹3,200 is ₹3,840 — more than the entire ₹3,200 by which income grew. Since expenditure also rose, savings must rise by strictly less than ₹3,200.
(c)
140% — 140% would mean savings climbing ₹4,480 while income gained only ₹3,200. It is what you reach by taking the percentages off the wrong bases; a bound check rules it out at once.

Concept

Savings = income − expenditure, so percentage changes on the two sides do not subtract. 20% up on income and 10% up on spending is not a 10% change in savings.

Expenditure is the larger piece — 80% of income here — so even a small percentage rise there absorbs much of the income gain, while savings, only a fifth of income, swing sharply.

Compute three rupee amounts — old savings, new income, new expenditure — and the answer falls out.

The ₹16,000 is decorative. Take income as 100 units: new savings = 1.2(100) − 1.1(80) = 32 against an old 20, a rise of 60% for any income at all.

Key facts

Savings = income − expenditure.
Percentage changes in income and expenditure never simply subtract to give the change in savings.
Old savings ₹3,200 and new savings ₹5,120 — a rise of ₹1,920, which is 60% of ₹3,200.
In units of income: 1.2 − (1.1 × 0.8) = 0.32 against an old 0.20, giving 60% whatever the income.

Study next

Income–expenditure–savings items where the savings ratio itself is askedSuccessive percentage change and the net-change formula a + b + ab⁄100Choosing a base of 100 when the supplied figure cancels out

Common traps

Subtracting the percentages (20% − 10%) and answering 10%
Measuring the rise against the new savings: 1,920 ÷ 5,120 = 37.5%
Adding 10% of income, rather than 10% of expenditure, as the extra spending

Most shifts carry one item of this shape, with SSC varying which two of income, expenditure and savings are given and which one the percentage change is asked about. The same shift reads spending as a percentage of income off a pie chart at Quant Q.4 (09 Sep 2024, 12:30).

Related PYQs

No directly related past PYQ was found.