Formulas To Solve Simple Interest Problems
Simple Interest Formulas
Simple Interest is the rate at which we lend or borrow money. In simple terms, when a lender lends money to a borrower, the borrower has to pay an extra amount of money to the lender. This extra amount of money is called interest. The interest on a sum borrowed for a certain period is called simple interest.
- Simple interest is calculated by multiplying the daily interest rate by the principal by the number of days that elapse between payments.
- This type of interest usually applies to short-term loans,.
- Basic Formula PxRxT/100

Formula for Simple Interest
Simple Interest Formulas
SI = P*r*t/100
Where,
P = money borrowed or lent out for a certain period(principal)
r = rate of interest
t = time period for which the amount is lent
- Principal = 100* SI/ R * T
- Rate = 100* SI/ P * T
- Time = 100* SI/ R * P
To get total amount of money
Amount = Principal + Interest
A = P + I
- Read Also – Tips & tricks to solve simple interest questions
Formulas based Questions on Simple Interest
Example 1
Find the simple interest on Rs. 65,000 at 6(2/3)% per annum for a period of 9 months?
Options
(A) 3520
(B) 3250
(C) 2350
(D) 5320
Explanations
Principle = 65,000
Rate = 6 \frac{2}{3} \
Time = 9 months
Principle = 65,000
Rate = \frac{20}{3} \
Time = \frac{3}{4} \
S.I = \frac{P*R*T}{100} \
= Rs. [65000×(20/3)×(3/4)×(1/100)]
= 3250
Correct Option(B)
Example 2
What sum of money will amount to Rs. 520 in 5 years and Rs. 568 in 7 years at simple interest?
Options
(A) 350
(B) 400
(C) 550
(D) 500
Explanations
Amount in 5 years = Rs 520
Amount in 7 years = Rs 568
2 years S.I = 568-520 = 48
Simple Interest for 1 years = latex \frac{48}{2} \ [/latex] = 24
5 years amount = Rs 520
For 1 years = 5*24 = 120
P = A – S.I = 520-120
P = 400
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