Solved Examples on Simple Interest
Having a thorough knowledge of S.I. definition, formulas concerning yearly and monthly along with the knowledge of terms like principal, rate, interest, amount and time. Let us step towards some simple interest questions for better understanding.
Solved Question 1: Determine the S.I. for a given principal amount of Rs. 4000, the duration is 2 years and the rate is 20%.
Solution:
Given terms;
P = 4000
R = 20%
T = 2 years
SI =?
Using the formula for SI;
\(S.I.=\frac{\left(P\times R\times T\right)}{100}\)
\(S.I.=\frac{\left(4000\times20\times2\right)}{100}\)
SI = 1600 rupees.
The same question can be solved for different years, you can check the below table for the same question being solved for different years.
| Time in Year | Calculation | Simple Interest | Amonut=Principal+Interest |
|---|---|---|---|
| 1 | SI=(4000X1X20)/100 | 800 | 4800 |
| 3 | SI=(4000X3X20)/100 | 2400 | 6400 |
| 5 | SI=(4000X5X20)/100 | 4000 | 8000 |
| 7 | SI=(4000X7X20)/100 | 5600 | 9600 |
| 9 | SI=(4000X7X20)/100 | 7200 | 11200 |
| 10 | SI=(4000X10X20)/100 | 8000 | 12000 |
Solved Question 2: Determine the simple interest for a given principal amount of Rs. 2000, the duration is 3 months and the rate of interest is 10%.
Solution: Given terms;
P = 2000
R = 10%
T = 3 months
SI = ?
Using the formula for SI;
\(S.I.=\frac{\left(P\times R\times x\right)}{12\times100}\)
Here x=Number of months
\(S.I.=\frac{\left(2000\times10\times3\right)}{12\times100}\)
⇒ 50
Solved Question 3: If the final amount on a certain amount of money becomes Rs. 720 in 2 years and Rs. 1020 in another 5 years in simple interest, then what is the annual rate of interest?
Solution: Formula used:
\(S.I.=\frac{\left(P\times R\times T\right)}{100}\)
Where P = principal
R = rate of interest
T = time
Principal = Amount – Interest
Calculation:
Money become 720 in 2 years and becomes 1020 in another 5 years
⇒ Interest in 5 years = (1020 – 720) = 300
⇒ interest in 1 year = 300/5 = 60
⇒ Interest in 2 year = 60 × 2 = 120
We are given that money becomes Rs. 720 in 2 years
Principal = Amount – Interest
Principal = 720 – 120 = 600
Let, rate of interest = r%
Accordingly,
(600 × 2 × r)/100 =120
⇒ r = 10
∴ The rate of interest is 10%
Check about Probability here.
Solved Question 4: A sum of Rs. 4000 is lent on simple interest at the rate of 10% per annum. The S.I. for 5 years is how much more than the S.I. for 3 years?
Solution:Given:
A sum of Rs.4000 is lent on S.I. at the rate of 10% per annum
P= 4000
R = 10%
Formula used:
\(S.I.=\frac{\left(P\times R\times T\right)}{100}\)
Calculation:
S.I for 5 years = (4000 × 5 × 10)/100 = 2000
S.I for 3 years = (4000 × 3 × 10)/100 = 1200
⇒ Difference between S.I for 5 years and S.I for 3 years = 2000 – 1200 = 800
∴ S.I. for 5 years is 800 more than S.I. for 3 years.
Here you can get more solved example Questions of Simple Interest.
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