SSC GD Constable Half-Yearly / Quarterly CI — Study Material & 13 Practice MCQs | ZestExam
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SSC GD Constable Half-Yearly / Quarterly CI
Study Material · Concept Notes · Shortcuts
This page covers SSC GD Constable Half-Yearly / Quarterly CI with complete concept notes, 13 graded practice MCQs, key points and exam-specific tips. Free to study.
Core ConceptRead 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 PatternsWhat 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 ExampleSolve 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
Exam TrapsCommon mistakes students make — avoid these
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.
Test Half-Yearly / Quarterly CI under exam conditions
The compound interest on ₹6,400 at 12.5% per annum, compounded half-yearly, for 1 year is:
Practice 2easy
A sum of ₹8,000 is invested at 12% per annum compound interest, compounded half-yearly. What will be the amount after 1 year?
Practice 3easy
₹5,000 is invested at 8% per annum compound interest, compounded quarterly. What is the compound interest earned after 6 months?
Practice 4easy
A principal amount becomes ₹10,404 after 1 year at 4% per annum compound interest, compounded half-yearly. What is the principal?
Practice 5easy
₹2,000 is invested at 10% per annum compound interest, compounded half-yearly. What will be the amount after 2 years?
Practice 6easy
₹12,000 is invested at 5% per annum compound interest, compounded quarterly. What is the amount after 9 months?
Practice 7medium
₹12,000 is invested at 8% per annum compound interest, compounded quarterly. Find the compound interest earned in 6 months.
Practice 8medium
A principal amount becomes ₹15,625 in 1 year when invested at 20% per annum compound interest, compounded half-yearly. What was the original principal?
Practice 9medium
The difference between compound interest and simple interest on a sum for 1 year at 16% per annum, compounded half-yearly, is ₹64. What is the principal?
Practice 10hard
A sum of ₹8,000 is invested at 20% per annum compound interest, compounded quarterly. What will be the amount after 1.5 years?
Practice 11hard
The difference between compound interest and simple interest on ₹10,000 for 1.5 years at 20% per annum, compounded half-yearly, is:
Practice 12hard
A sum of money becomes 4 times itself in 2 years at a certain rate of compound interest, compounded quarterly. What is the rate of interest per annum?
Practice 13hard
₹5,000 is invested at 12% per annum compound interest, compounded quarterly. After 9 months, the amount will be approximately:
60-Second Revision — Half-Yearly / Quarterly CI
Remember: Divide rate by compounding frequency (2 for half-yearly, 4 for quarterly), multiply time by the same number
Formula: A = P × (1 + R/(100×n))^(t×n) — this works for ALL compounding frequencies
Trap: Don't forget CI = Amount − Principal; calculate both separately
Quick Check: In 1 year with quarterly CI at 20% p.a., effective rate ≈ 21.55% (not 20%)
Pattern: More frequent compounding always gives MORE interest for same P, R, and t
Always verify: After substitution, ensure exponent = compounding periods per year × time in years