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 Barbara borrowed a sum of $3550 at 6% simple interest for 4 years.
(2) Calculate the amount due after 9 years if Barbara borrowed a sum of $5550 at a rate of 10% simple interest.
(3) Calculate the amount due if Linda borrowed a sum of $3350 at 3% simple interest for 3 years.
(4) Calculate the amount due after 10 years if Michael borrowed a sum of $5300 at a rate of 6% simple interest.
(5) Calculate the amount due after 9 years if Richard borrowed a sum of $5600 at a rate of 3% simple interest.
(6) Calculate the amount due after 10 years if Patricia borrowed a sum of $5150 at a rate of 10% simple interest.
(7) Calculate the amount due after 9 years if Patricia borrowed a sum of $5150 at a rate of 4% simple interest.
(8) Lisa took a loan of $6100 at the rate of 9% simple interest per annum. If he paid an amount of $11590 to clear the loan, then find the time period of the loan.
(9) If Susan paid $4380 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.
(10) Donna had to pay $5577.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.