Compound Interest Questions with Solutions | Set 1 (Q1 to Q10)

This set contains Compound Interest Questions with Solutions — Set 1 (Q1 to Q10) covering a mix of question types and difficulty levels — from basic to advanced — exactly as asked in real competitive exams.

Solutions are written in a simple, step-by-step notebook style for easy self-study and quick understanding. Each solution is broken down step by step so even the toughest question feels easy. These questions are hand-picked for students preparing for SSC CGL, SSC CHSL, CAT, Bank PO, Bank Clerk, UPSC CSAT, Railway RRB, AMCAT, eLitmus, TCS NQT and all campus placement aptitude tests. International students preparing for GRE, GMAT, SAT, ACT, MAT and all Numerical Reasoning Tests will find these equally useful.

✏️ Attempt each question on your own first — then check the solution below.

1. A invested a sum of Rs. 64000 for 3 years at compound interest and received an amount 74088 Rs. on maturity. What is the rate of interest.

2. On what principal will the compound interest for 3 years at 5% p.a. amount to 63.05 .

3. Rs. 10000 is borrowed at CI at the rate of 1% for first year, 2% for second year and 3% for third year. Find the amount to be paid after 3 years.

4. Find the amount of Rs. 1000 in 1 year at 5 p.a., compound interest payable half-yearly.

5. Find the amount on Rs. 500000 in 1y8m at 24% p.a., compound interest being calculate in every 5 months.

6. Find the compound interest of third year only on Rs. 10000 in 9 months at 4% p.a. interest payable quarterly.

7. Find the compound interest on Rs. 16000 in 3 months at 5% p.a., interest payable quarterly.

8. What principal will amount to Rs. 7935 in 2 years at 15% p.a. compound interest.

9. At what rate percent compound interest, will Rws. 256 amount to Rs. 289 in 2 years ?

10. On what sum will the amount for 2.75 years at 10% p.a. becomes Rs. 123507.125 ?

1. A invested a sum of Rs. 64000 for 3 years at compound interest and received an amount 74088 Rs. on maturity. What is the rate of interest.
Sol:

2. On what principal will the compound interest for 3 years at 5% p.a. amount to 63.05 .
Sol:
5% = \(\frac{1}{{20}}\)

∴ P = 8000 × 0.05 = 400 Rs.         Answer

Method(2): From table we remember that combined rate of 5% for 3 years is 15.7625%

∴ CI = \(\frac{{P \times 15.7625 \times 1}}{{100}}\)
= 400                     Answer

3. Rs. 10000 is borrowed at CI at the rate of 1% for first year, 2% for second year and 3% for third year. Find the amount to be paid after 3 years.
Sol:
Method(1):

∴ total amount after 3 years
= 100000 + (1000 + 2000 + 3000) + (60 + 30 + 20 + 0.6)
= 106110.6               Answer
Method(2):

∴ CI = 6.1106% of 100000
= 6110.6
∴ Amount = 100000 + 6110.6
= 106110.6 Rs.               Answer

Method(3):  1% = \(\frac{1}{{100}}\)         2% = \(\frac{1}{{50}}\)            3% = \(\frac{3}{{100}}\)

4. Find the amount of Rs. 1000 in 1 year at 5 p.a., compound interest payable half-yearly.
Sol:
Half yearly i.e. in 6-months.
∴ r = \(\frac{5}{{12}} \times 6\% = \frac{5}{2}\% \)
& term = 1×2 = 2 half-yearly
Method(1):
now find equivalent rate for 2 half-yearly term = 2.5 + 2.5 + \(\frac{{2.5 \times 2.5}}{{100}}\)
= 5.0625%
∴ CI = 1000×5.0625% = 50.625
∴ amount = 1000 + 50.625
 =1050.625      Answer

Method(2):

5. Find the amount on Rs. 500000 in 1y8m at 24% p.a., compound interest being calculate in every 5 months.
Sol:-        
P = 500000
r = 24% p.a.
t = 1y 8m = 20m
compounded in every 5 months
∴ r’ = \(\frac{{24}}{{12}} \times 5\) = 10%
& term = \(\frac{{20}}{5}\) = 4
Now apply tree method

∴ CI = 50000 × 4 + 5000 × 6 + 500 × 4 + 50
= 232050
∴ amount = 500000 + 232050
= 732050 Rs.             Answer

Method(2):     r’ = 10% = \(\frac{1}{{10}}\)

Method(3):

10%     10%     10%      10%
⟶ 10 + 10 + \(\frac{{10 \times 10}}{{100}}\) = 21%
21 + 10 + \(\frac{{21 \times 10}}{{100}}\)
= 32.1
⟶ 32.1 + 10 + \(\frac{{32.1 \times 10}}{{100}}\)
= 46.41%
∴ CI = 46.41% of 500000
= 232050
∴ A = 500000 + 232050 = 732050 Rs.            Answer

6. Find the compound interest of third yera only on Rs. 10000 in 9 months at 4% p.a. interest payable quarterly.
Sol:
Interest is payable quaterly & there are 4 quarters in a year. So interest will be payable every \(\frac{{12}}{4}\) = 3 months.
P = 10000
r = 4% p.a. ⟹ r’ = \(\frac{4}{{12}}\)×3 = 1%
t = 9 months ⟹ t’ = \(\frac{9}{3}\) = 3

∴ CI of 3ʳᵈ year = 100 + 1 + 1 + \(\frac{1}{{100}}\)
= 102.01     Answer

7. Find the compound interest on Rs. 16000 in 3 months at 5% p.a., interest payable quarterly.
Sol:
P = 16000
r = 5%
t = 3 months
compounding-period = 3 months (quarterly)
∴ r’ = \(\frac{5}{{12}}\)×3 = \(\frac{5}{4}\)% = \(\frac{1}{{80}}\)%
t’ = \(\frac{3}{3}\) = 1

8. What principal will amount to Rs. 7935 in 2 years at 15% p.a. compound interest.
Sol:
15% = \(\frac{3}{{20}}\)

Method(2):
15 + 15 + \(\frac{{15 \times 15}}{{100}}\) = 32.25%
∴ CI = P × 32.25%
A = P(1 + 32.25%)
P = \(\frac{{7935}}{{1.3225}}\)
P = 6000     Answer

Method(3):

9. At what rate percent compound interest, will Rws. 256 amount to Rs. 289 in 2 years ?
Sol:

10. On what sum will the amount for 2.75 years at 10% p.a. becomes Rs. 123507.125 ?
Sol:
time = 2.75 years
r = 10% = \(\frac{1}{{10}}\)

Now CI of 3ʳᵈ year = 100 + 10 + 10 + 1 = 121
but in question whole third year is not taken only 0.75 year is taken
∴ CI for 0.75 year in third year = 121 × 0.75
                                                = 90.75
∴ total CI of 2.75 years = 
100 × 2 + 10 + 90.75
 = 300.75
∴ A = P + CI
= 1000 + 300.75

✅ Well done on completing Set 1!

Continue practising with Compound Interest Questions 11 to 20 → Set 2 or revisit the Compound Interest Concept Page to strengthen your formulas and tricks before moving ahead.

Consistent practice is the key to mastering compound interest for SSC CGL, SSC CHSL, CAT, Bank PO, Bank Clerk, UPSC CSAT, Railway RRB, AMCAT, eLitmus, TCS NQT and international exams including GRE, GMAT, SAT, ACT, MAT and all Numerical Reasoning Tests. Want to understand the concept better? Read about Compound Interest on Wikipedia before attempting the next set.

This page is part of our complete series of compound interest questions with solutions for competitive exams — covering every question type from basic to advanced so you can build speed, accuracy and confidence. Practising these questions regularly will also strengthen your core compound interest concept before your exam day.