Question:
Calculate the amount due if Richard borrowed a sum of $3600 at 9% simple interest for 3 years.
Correct Answer
$4572
Solution And Explanation
Solution
Given,
Principal (P) = $3600
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) = $3600 × 9% × 3
= $3600 ×9/100 × 3
= 3600 × 9 × 3/100
= 32400 × 3/100
= 97200/100
= $972
Thus, Simple Interest = $972
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 = $3600 + $972
= $4572
Thus, Amount to be paid = $4572 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 = $3600
Rate of Simple Interest (SI) or (R) = 9%
And, Time (t) = 3 years
Thus, Amount (A)
= $3600 + ($3600 × 9% × 3)
= $3600 + ($3600 ×9/100 × 3)
= $3600 + (3600 × 9 × 3/100)
= $3600 + (32400 × 3/100)
= $3600 + (97200/100)
= $3600 + $972 = $4572
Thus, Amount (A) to be paid = $4572 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 $3600, the simple interest in 1 year
= 9/100 × 3600
= 9 × 3600/100
= 32400/100 = $324
Thus, simple interest for 1 year = $324
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $324 × 3 = $972
Thus, Simple Interest (SI) = $972
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3600 + $972
= $4572
Thus, Amount to be paid = $4572 Answer
Similar Questions
(1) Calculate the amount due if John borrowed a sum of $3200 at 2% simple interest for 3 years.
(2) Calculate the amount due after 9 years if William borrowed a sum of $5500 at a rate of 3% simple interest.
(3) James took a loan of $4000 at the rate of 9% simple interest per annum. If he paid an amount of $7240 to clear the loan, then find the time period of the loan.
(4) How much loan did Ryan borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $9480 to clear it?
(5) How much loan did Mark borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $7680 to clear it?
(6) In how much time a principal of $3050 will amount to $3294 at a simple interest of 2% per annum?
(7) How much loan did Kimberly borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $7315 to clear it?
(8) Find the amount to be paid if Robert borrowed a sum of $5100 at 6% simple interest for 8 years.
(9) Matthew took a loan of $6400 at the rate of 8% simple interest per annum. If he paid an amount of $11008 to clear the loan, then find the time period of the loan.
(10) Patricia took a loan of $4300 at the rate of 9% simple interest per annum. If he paid an amount of $7009 to clear the loan, then find the time period of the loan.