Simple Interest
The amount of money charged when a person borrows money, e.g., from a bank, is called interest (I). The amount of money borrowed is called principal (P). Interest rate (R) is given as a percentage and is usually taken per year or per annum (p.a). To calculate simple interest, we use the formula:
I=100P×R×T
Where:
I: Interest
P: Principal (The money borrowed or invested)
R: Rate of interest (percentage per annum)
T: Time in years
A: Amount (The sum of principal and interest)
Example 1
Find the simple interest on 18,000 sh for 2 years at a rate of 6%.
Solution:
Given:
Principal (P): 18,000 sh
Rate (R): 6%
Time (T): 2 years
Formula: I=100P×R×T
I=10018,000×6×2=100216,000=2,160 sh
Therefore, the simple interest is 2,160 sh.
Example 2
Calculate the simple interest on 25,000 sh for 3 years at a rate of 8%.
Solution:
Given:
Principal (P): 25,000 sh
Rate (R): 8%
Time (T): 3 years
Formula: I=100P×R×T
I=10025,000×8×3=100600,000=6,000 sh
Therefore, the simple interest is 6,000 sh.
Example 3
A person borrows 50,000 sh for 4 years at a rate of 5%. Find the simple interest.
Solution:
Given:
Principal (P): 50,000 sh
Rate (R): 5%
Time (T): 4 years
Formula: I=100P×R×T
I=10050,000×5×4=1001,000,000=10,000 sh
Therefore, the simple interest is 10,000 sh.
Example 4
Find the simple interest on 12,000 sh for 6 years at a rate of 10%.
Solution:
Given:
Principal (P): 12,000 sh
Rate (R): 10%
Time (T): 6 years
Formula: I=100P×R×T
Calculation:
I=10012,000×10×6=100720,000=7,200 sh
Therefore, the simple interest is 7,200 sh.
Example 5
If a person deposits 15,000 sh in a bank for 2 years at an interest rate of 12%, calculate the interest.
Solution:
Given:
Principal (P): 15,000 sh
Rate (R): 12%
Time (T): 2 years
Formula: I=100P×R×T
I=10015,000×12×2=100360,000=3,600 sh
Therefore, the simple interest is 3,600 sh.
Example 6
Calculate the simple interest on 40,000 sh for 5 years at a rate of 7%.
Solution:
Given:
Principal (P): 40,000 sh
Rate (R): 7%
Time (T): 5 years
Formula: I=100P×R×T
I=10040,000×7×5=1001,400,000=14,000 sh
Therefore, the simple interest is 14,000 sh.