SSC CGL 2024 Tier-I · 19 September 2024, Shift 1 · Quantitative Aptitude · Question 19 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 10 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.

Aman invested a sum of money in scheme A at the rate of 8% p.a. for a period of 5 years on simple interest. He invested four times of the sum of scheme A in scheme B at the rate of 5% p.a. for 7 years on simple interest. He received a total interest amount of ₹1,620. How much (in ₹) did he invest in scheme B?

(a)900
(b)3,200
(c)2,400
(d)3,600

Answer

Why

Correct — D. Call the scheme A sum P. Scheme B then holds 4P.

SI = P × R × T ⁄ 100
A: P × 8 × 5 ⁄ 100 = 0.4P
B: 4P × 5 × 7 ⁄ 100 = 1.4P

0.4P + 1.4P = 1.8P = 1620
P = 1620 ⁄ 1.8 = 900

The question asks for scheme B, not for P:
4 × 900 = ₹3,600 → option (d)

Why the others are wrong

(a)
900 — 900 is P itself, the scheme A sum. The stem asks what went into scheme B, which is the larger investment. Solving correctly and answering the wrong quantity is the commonest loss on this item.
(b)
3,200 — 3,200 needs P = 800, and 800 run through both schemes returns 1.8 × 800 = ₹1,440 of interest, not the ₹1,620 given. Feed any option back through both schemes to test it.
(c)
2,400 — 2,400 implies P = 600, whose two interests total ₹1,080 — well short of ₹1,620. It is the kind of round figure that looks plausible until it is checked against the stated interest.

Concept

Simple interest is SI = P × R × T ⁄ 100. The principal never changes, so every year of the term earns the same amount.

When one sum is stated as a multiple of another, name the smaller one P and write both interests in terms of P. Two unknowns collapse into one equation, and you never need the actual money to compare the two interests.

The step candidates lose is the last one: the equation solves for P, but the question can ask for the other sum.

Rate and time are supplied for each scheme, so nothing needs converting. Both are plain products — the word simple rules out any compounding, and reading it as compound would make the totals unreachable from the options.

Key facts

SI = P × R × T ⁄ 100, and the principal stays fixed for the whole term.
8% for 5 years returns 0.40 of the principal as interest.
5% for 7 years returns 0.35 of the principal as interest.
1.8P = ₹1,620 gives P = ₹900, so scheme B holds 4P = ₹3,600.

Study next

Splitting one sum into two parts lent at different simple-interest ratesReading a blended annual yield back into its two component ratesThe difference between simple and compound interest over two and three years

Common traps

Stopping at P = 900 when the question asks for the scheme B sum.
Attaching the 8% rate to the larger investment and 5% to the smaller.
Reading ₹1,620 as one scheme's interest rather than the combined total.

The dress here is two sums running at different rates, with only the combined interest given.

Also asked 10 Sep 2024, 09:00, Quant Q.2 (₹4,000 lent in two parts at 8% and 10%) and 18 Sep 2024, 12:30, Quant Q.20 (₹2,00,000 split so the blended yield is 4.7%).

Related PYQs

No directly related past PYQ was found.