Compound Interest Tests — Pick a Level and Start
Tap a level to see every test in it. Level 1 is set at real SSC CGL difficulty — start there the day you finish the concept. Level 2 is pitched above the exam, to push accuracy under pressure.
Level 1 SSC CGL Level Checking… View tests
Same difficulty as the real SSC CGL paper — one idea per question. The interest or the amount for two and three years; working back from an amount or an interest figure to the sum; half-yearly, quarterly and eight-monthly compounding; a different rate in each year; the rate or the time from a clean growth ratio; the CI–SI gap over two and three years; the interest of one particular year; equal instalments; and depreciation. A steady score here means the chapter is exam-ready.
Level 2 Above SSC CGL Level Checking… View tests
Harder than the exam asks, because every question chains two ideas or runs one backwards. A gap at one rate converted into the gap at another; a deposit that compounds, loses a withdrawal and compounds again; a half-yearly figure that must become a yearly one before the real question starts; a rate dug out of two consecutive years' interests; a part payment carried forward to the due date; an instalment split into its interest and its principal; and an inheritance divided so two children of different ages end level. Clear these and the real paper feels easy.
Compound interest is simple interest with one change, and the whole chapter follows from it: the interest of each year is added to the sum, so the next year earns on that larger sum too. Write the year's growth as a multiplying factor — 1 + R/100 — and almost every question in the chapter becomes a matter of applying that factor the right number of times, or dividing it out the right number of times.
The marks go on two things. The first is the conversion: when interest is added twice a year the rate is halved and the periods doubled, and 18 months is three half-year periods, not one and a half years. The second is the shape of the interest itself — two years at R% do not add 2R% to the sum but a little more, and that little more is exactly what every CI–SI difference question is about. Each test puts twenty-five compound interest questions in front of you in one sitting, which is what makes the recurring shapes visible.
How Many Compound Interest Questions Are Asked in SSC CGL?
Compound interest is a near-certain question in Tier II and a frequent one in Tier I. It is almost always set alongside simple interest, and the two share every letter of the formula.
| Chapter | Tier I (out of 25) | Tier II Paper I (out of 30) |
|---|---|---|
| Compound Interest | 1–2 | 1–2 |
| Simple Interest | 1–2 | 2–3 |
| Percentage | 1–2 | 2–3 |
| Profit, Loss & Discount | 2–3 | 3–4 |
Counts vary by shift. A question that compares compound interest with simple interest is counted here, since the compound side is what makes it hard — but it cannot be solved without the simple interest chapter either.
What You Will Practice in the Compound Interest Chapter
Core topics
- The interest and the amount for two, three, four and five years, using the multiplying factor
- Working back from an amount to the sum, and from an interest figure to the sum
- Present value — what a payment due later is worth today
- Whole years followed by a part year, where the leftover months earn simple interest
- Half-yearly compounding: halve the rate, double the periods
- Quarterly compounding, and conversion periods of four and eight months
- Nominal rate against effective rate, and converting a rate between two frequencies
- A different rate in each year, and the single rate equivalent to a run of them
- The rate from a sum and an amount, from an interest figure, or from a growth multiple
- The time from a sum and an amount, and doubling or trebling relations
- The difference between compound and simple interest over two years and over three
- The interest of one particular year, and the rate from two consecutive years' interests
- Equal annual and half-yearly instalments, and the cash price behind them
- One scheme's proceeds reinvested in another, and withdrawals part way through
- A sum split between two schemes, by a ratio or so the interests come out equal
- Deposits made every year or twice a year, and early settlement of a debt
- Depreciation of a value and growth of a population at a compound rate
Formulas worth memorising
| Situation | Formula |
|---|---|
| Amount, compounded yearly | A = P(1 + R/100)n |
| Compound interest | CI = A − P = P[(1 + R/100)n − 1] |
| Sum from the amount | P = A / (1 + R/100)n |
| Half-yearly compounding | A = P(1 + R/200)2n |
| Quarterly compounding | A = P(1 + R/400)4n |
| Conversion period of m months | rate = Rm/1200, periods = 12n/m |
| Whole years plus a fraction f of a year | A = P(1 + R/100)n(1 + fR/100) |
| A different rate each year | A = P(1 + R₁/100)(1 + R₂/100)… |
| Interest of the nth year | P(1 + R/100)n−1 × R/100 |
| CI − SI, 2 years | D = P(R/100)² |
| CI − SI, 3 years | D = P(R/100)²(3 + R/100) |
| Half-yearly against yearly, 1 year | D = P(R/200)² |
| Sum becomes n times itself | (1 + R/100)t = n |
| Two amounts one year apart | R = (A₂ − A₁) / A₁ × 100 |
| Effective rate from a nominal rate | [(1 + R/k/100)k − 1] × 100, k periods a year |
| Debt cleared by n equal instalments | P = x/(1+R/100) + x/(1+R/100)² + … |
| Depreciation over n years | V(1 − R/100)n |
The two difference rows are the ones to hold on to. Over two years the whole gap between compound and simple interest is one year's interest on the first year's interest, which is why P(R/100)² is such a small number — and why SSC likes giving it and asking for the sum.
The three mistakes that cost the most marks
- Not converting when the compounding is not yearly. Half-yearly means the rate is halved and the periods doubled — 20% per annum for 2 years is four periods at 10%, not two at 20% or two at 10%. Quarterly quarters the rate and takes four times the periods.
- Treating two years as
2R%of the sum. Two years at 10% add 21%, not 20%; at 20% they add 44%, not 40%. The extra is the interest on the first year's interest, and every CI–SI question is built on it. - Working a single year's interest on the original sum. The interest of the third year is the rate applied to the amount standing when the third year begins, not to the sum. Each year's interest is larger than the one before.
Solved Examples — SSC CGL Compound Interest
1.1, so two years multiply by 1.1 × 1.1 = 1.21. The amount is 12000 × 1.21 = 14,520, so the interest is 14520 − 12000 = 2,520. Year by year it reads the same way: 10% of 12,000 is 1,200, taking the sum to 13,200, and 10% of 13,200 is 1,320 — together 2,520. Simple interest would have given only ₹2,400 over the same two years, and the extra ₹120 is the second year's interest on the first year's 1,200. Answer: ₹2,5201.1² = 1.21, so the amount is 8000 × 1.21 = 9,680. Period by period: 10% of 8,000 is 800, taking the sum to 8,800, then 10% of 8,800 is 880. Using 20% for each half year would give ₹3,520 — far too much. Answer: ₹1,680D = P(R/100)² = 15000 × (0.1)² = 15000 × 0.01. Checking it the long way: SI is 15000 × 10 × 2 / 100 = 3,000 and CI is 15000(1.21 − 1) = 3,150. The gap is the second year's interest on the first year's 1,500. Answer: ₹1501.1³ = 1.331, so the sum is 5324 / 1.331. Do not subtract the interest as though it were simple — under compounding the yearly interest is not a fixed amount. Forwards it reads 4000 → 4400 → 4840 → 5324. Answer: ₹4,000How the Compound Interest Chapter Tests Work
- 25 questions per test, with a full question palette — answered, skipped, marked for review, not visited.
- Optional 15-minute timer — with the clock to build exam speed, without it while you are still learning the chapter.
- Marking: +2 correct, −0.5 wrong, 0 unattempted — the same scheme as the real paper.
- Solutions, shortcut tricks and concept notes open after you submit, question by question.
- English and हिंदी, chosen at the start of every test.
- Free with a TrickySSC account — sign in once with Google or your mobile number, and every test is open to you.
How to Prepare Compound Interest for SSC CGL
- Do percentage and simple interest first. Every rate here is a percentage, and the CI–SI questions — a good share of the chapter — cannot be attempted without the simple interest formula.
- Learn the factors, not the formula. Keep
1.1² = 1.21,1.1³ = 1.331,1.2² = 1.44,1.2³ = 1.728,1.25² = 1.5625and1.05² = 1.1025in your head. Most Tier I questions are one multiplication once you know the factor. - Write awkward rates as fractions.
12½% = 1/8so the factor is9/8;16⅔% = 1/6gives7/6; 25% gives5/4. Fractions keep the arithmetic exact and the cancelling obvious. - Convert the compounding before anything else. Halve and double for half-yearly, quarter and quadruple for quarterly, and count the periods in the time given rather than the years.
- Memorise the two difference formulas.
P(R/100)²for two years andP(R/100)²(3 + R/100)for three. They are asked in both directions and they save a full minute each time. - Do Level 1 untimed, the same day you finish the theory. It is set at real SSC CGL difficulty; the aim is picking the right factor and the right number of periods, not speed.
- Repeat Level 1 with the 15-minute clock on, then move to Level 2. A Tier I compound interest question that takes more than about fifty seconds usually means the factor was rebuilt from scratch instead of recalled.
- Verify against a real paper. Once Level 1 is consistent under the clock, attempt a previous year paper and then a full mock test under locked sectional timing.
All SSC CGL Chapter Wise Tests
Every chapter below has its own free Level 1 and Level 2 tests with full solutions.
Browse all 45 chapter tests — Maths (35) · Reasoning (10)
- Number System
- Rule of Divisibility
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- LCM & HCF
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- Percentage
- Profit & Loss
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- Compound Interest
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SSC CGL चक्रवृद्धि ब्याज (Compound Interest) चैप्टर टेस्ट — हिंदी में
चक्रवृद्धि ब्याज में हर वर्ष का ब्याज मूलधन में जुड़ जाता है, इसलिए अगले वर्ष ब्याज इस बढ़े हुए मूलधन पर लगता है। यही बात इसे साधारण ब्याज से अलग करती है और यही इसका पूरा विचार है। मूल सूत्र A = P(1 + R/100)n है, और कोष्ठक वाला भाग गुणक है — हर वर्ष के लिए मूलधन को इससे एक बार गुणा किया जाता है।
सबसे अधिक अंक दो बातों पर कटते हैं। पहली: अर्धवार्षिक संयोजन में दर आधी और अवधियाँ दोगुनी करनी पड़ती हैं — 20% प्रति वर्ष का अर्थ है प्रति अर्धवर्ष 10% और वर्ष में दो अवधियाँ। दूसरी: 2 वर्ष का ब्याज मूलधन का 2R% नहीं होता, बल्कि उससे कुछ अधिक, क्योंकि दूसरे वर्ष पहले वर्ष के ब्याज पर भी ब्याज मिलता है। इसी अंतर से CI और SI का अंतर बनता है, जो 2 वर्ष में P × (R/100)² होता है।
TrickySSC पर इस अध्याय के सभी टेस्ट हिंदी में उपलब्ध हैं — प्रश्न, विकल्प, विस्तृत हल और शॉर्टकट ट्रिक सब हिंदी में। दो स्तर हैं: लेवल 1 (SSC CGL के स्तर का) और लेवल 2 (SSC CGL से कठिन)। प्रत्येक टेस्ट में 25 प्रश्न, वैकल्पिक 15 मिनट का टाइमर और +2 / −0.5 की वही मार्किंग जो असली परीक्षा में होती है।