Question:
Calculate the amount due if John borrowed a sum of $3200 at 9% simple interest for 3 years.
Correct Answer
$4064
Solution And Explanation
Solution
Given,
Principal (P) = $3200
Rate of Simple Interest (SI) = 9%
Time (t) = 3 years
Thus, Amount (A) = ?
The Rate of Interest is always calculated per annum, i.e. per year.
Thus, here 9% simple interest means, Rate of Simple Interest (SI) is 9% per annum.
Method (1) Using Formula
Calculation of Simple Interest
Formula to Calculate Simple Interest
Simple Interest (SI) = Principal × Rate × Time
Thus, Simple Interest (SI) = $3200 × 9% × 3
= $3200 ×9/100 × 3
= 3200 × 9 × 3/100
= 28800 × 3/100
= 86400/100
= $864
Thus, Simple Interest = $864
Calculation of Amount
The total money paid to the lender by a borrower is called the Amount.
In other words, sum of priciple and interest is called the Amount.
Formula to Calculate the Amount
Amount = Principal + Interest
Thus, Amount = $3200 + $864
= $4064
Thus, Amount to be paid = $4064 Answer
Method (2)
Calculation of Amount when Principal, Rate of Simple Interest and Time are given
Calculation of Amount directly using Principal, SI, and Time
Formula to calculate the Amount
Amount (A) = Principal (P) + Principal(P) × Rate of Interest (SI) × Time (t)
⇒ A = P + PRT
Here in the question, P = $3200
Rate of Simple Interest (SI) or (R) = 9%
And, Time (t) = 3 years
Thus, Amount (A)
= $3200 + ($3200 × 9% × 3)
= $3200 + ($3200 ×9/100 × 3)
= $3200 + (3200 × 9 × 3/100)
= $3200 + (28800 × 3/100)
= $3200 + (86400/100)
= $3200 + $864 = $4064
Thus, Amount (A) to be paid = $4064 Answer
Method (3) Unitary Method
Calculation of Amount using Unitary Method
Calculation of Interest using Unitary Method
Here, given Rate of Simple Interest = 9%
This, means, $9 per $100 per year
∵ For $100, the simple interest for 1 year = $9
∴ For $1, the simple interest for 1 year = 9/100
∴ For $3200, the simple interest in 1 year
= 9/100 × 3200
= 9 × 3200/100
= 28800/100 = $288
Thus, simple interest for 1 year = $288
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $288 × 3 = $864
Thus, Simple Interest (SI) = $864
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3200 + $864
= $4064
Thus, Amount to be paid = $4064 Answer
Similar Questions
(1) Find the amount to be paid if Christopher borrowed a sum of $6000 at 7% simple interest for 7 years.
(2) What amount will be due after 2 years if William borrowed a sum of $3250 at a 7% simple interest?
(3) Calculate the amount due if Thomas borrowed a sum of $3800 at 4% simple interest for 3 years.
(4) How much loan did Steven borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $8250 to clear it?
(5) Jessica took a loan of $5500 at the rate of 6% simple interest per annum. If he paid an amount of $7480 to clear the loan, then find the time period of the loan.
(6) Calculate the amount due after 10 years if Patricia borrowed a sum of $5150 at a rate of 9% simple interest.
(7) What amount does Susan have to pay after 6 years if he takes a loan of $3650 at 7% simple interest?
(8) Richard took a loan of $5200 at the rate of 8% simple interest per annum. If he paid an amount of $8944 to clear the loan, then find the time period of the loan.
(9) Find the amount to be paid if Charles borrowed a sum of $5900 at 6% simple interest for 7 years.
(10) Michael took a loan of $4600 at the rate of 9% simple interest per annum. If he paid an amount of $7084 to clear the loan, then find the time period of the loan.