Study Material — 7 PYQs (2020–2020) · Concept Notes · Shortcuts
IBPS RRB PO Half-Yearly / Quarterly CI is a frequently tested subtopic — 7 previous year questions from 2020–2020 papers are included below with concept notes, key rules and shortcut tricks.
IBPS RRB PO Half-Yearly / Quarterly CI — Past Exam Questions
7 questions from actual IBPS RRB PO papers · all shown free · click option to reveal solution
Exam Q 12020Previous Year Pattern
₹20,000 is invested at 16% per annum compound interest, compounded quarterly. What is the difference between the compound interest for the 1st quarter and the 2nd quarter?
Test Half-Yearly / Quarterly CI under exam conditions
₹12,000 is invested at 8% per annum compound interest, compounded quarterly. Find the compound interest earned in 6 months.
Exam Q 32020Previous Year Pattern
A sum of money becomes ₹9,331 in 18 months at 20% per annum compound interest, compounded half-yearly. Find the principal.
Exam Q 42020Previous Year Pattern
A principal amount becomes ₹15,625 in 1 year at 20% per annum compound interest, compounded half-yearly. What is the principal?
Exam Q 52020Previous Year Pattern
A bank offers two schemes: Scheme A gives 12% per annum simple interest, and Scheme B gives 10% per annum compound interest, compounded half-yearly. A person invests ₹10,000 in each scheme for 2 years. What is the difference in the final amounts?
Exam Q 62020Previous Year Pattern
A sum of money doubles itself in 3 years at a certain rate of compound interest, compounded half-yearly. At the same rate, in how many years will it become 8 times?
Exam Q 72020Previous Year Pattern
A sum of ₹8,000 is invested at 12% per annum compound interest, compounded half-yearly. What is the compound interest earned in 18 months?
Concept Notes
Half-Yearly / Quarterly CI— Rules & Concept
💡
Core Concept
Read this first — the foundation of the topic
→Core Concept
When you deposit money in a bank, the bank usually adds interest once a year. But some banks add interest twice a year (half-yearly) or four times a year (quarterly). Each time interest is added, it becomes part of the new principal, and the next interest is calculated on this larger amount. This is why more frequent compounding gives you more interest
💡Key Rules
For half-yearly CI: The rate is divided by 2, and time is multiplied by 2.
For quarterly CI: The rate is divided by 4, and time is multiplied by 4
🔑Formula
A = P × (1 + R/(100×n))^(t×n)
Where:
- A = Amount after interest
- P = Principal (original money)
- R = Annual rate of interest (%)
- n = Number of times compounded per year (2 for half-yearly, 4 for quarterly)
- t = Time in years
- CI = A − P
📊
Exam Patterns
What examiners ask — read before attempting PYQs
SSC CGL typically asks: Compare CI for different compounding periods, find CI amount, or calculate effective rate.
Shortcut/Trick:
For half-yearly: Use R/2 and 2t. For quarterly: Use R/4 and 4t. Always remember the rate gets divided and time gets multiplied by the same number.
✏️
Worked Example
Solve this step-by-step before moving on
1
Step 1
Identify n = 4 (quarterly)
2
Step 2
Apply formula: A = 8000 × (1 + 20/(100×4))^(1×4)
3
Step 3
A = 8000 × (1 + 5/100)^4
4
Step 4
A = 8000 × (1.05)^4
5
Step 5
A = 8000 × 1.2155 = 9724
6
Step 6
CI = 9724 − 8000 = Rs 1724
Common Mistake:
Students forget to divide the rate by the compounding frequency. They use the full annual rate instead of R/2 or R/4, leading to wrong answers. Always reduce the rate first.
Key Points to Remember
Half-yearly CI: Divide rate by 2, multiply time by 2
Quarterly CI: Divide rate by 4, multiply time by 4
Formula: A = P(1 + R/(100n))^(tn) where n = compounding frequency
More frequent compounding = higher final amount
CI = Amount − Principal (always calculate both separately)
In 1 year, quarterly compounding gives more interest than half-yearly
Exam-Specific Tips
For half-yearly compounding, the effective rate formula is: (1 + R/200)^2 − 1
For quarterly compounding in 1 year, total compounding periods = 4
Half-yearly means n = 2, so rate becomes R/2 for each period
Quarterly means n = 4, so rate becomes R/4 for each period
If time is 2 years with quarterly compounding, total periods = 8
Compound Interest formula with frequency: A = P(1 + r/100)^n where r is periodic rate and n is total periods
For half-yearly: 1 year = 2 periods, 2 years = 4 periods, 3 years = 6 periods
Practice MCQs
Half-Yearly / Quarterly CI — Practice Questions
4graded MCQs · easy to hard · full solution & trap analysis