Question:
Calculate the amount due if Michael borrowed a sum of $3300 at 9% simple interest for 3 years.
Correct Answer
$4191
Solution And Explanation
Solution
Given,
Principal (P) = $3300
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) = $3300 × 9% × 3
= $3300 ×9/100 × 3
= 3300 × 9 × 3/100
= 29700 × 3/100
= 89100/100
= $891
Thus, Simple Interest = $891
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 = $3300 + $891
= $4191
Thus, Amount to be paid = $4191 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 = $3300
Rate of Simple Interest (SI) or (R) = 9%
And, Time (t) = 3 years
Thus, Amount (A)
= $3300 + ($3300 × 9% × 3)
= $3300 + ($3300 ×9/100 × 3)
= $3300 + (3300 × 9 × 3/100)
= $3300 + (29700 × 3/100)
= $3300 + (89100/100)
= $3300 + $891 = $4191
Thus, Amount (A) to be paid = $4191 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 $3300, the simple interest in 1 year
= 9/100 × 3300
= 9 × 3300/100
= 29700/100 = $297
Thus, simple interest for 1 year = $297
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $297 × 3 = $891
Thus, Simple Interest (SI) = $891
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3300 + $891
= $4191
Thus, Amount to be paid = $4191 Answer
Similar Questions
(1) How much loan did Michelle borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $8687.5 to clear it?
(2) Calculate the amount due after 10 years if James borrowed a sum of $5000 at a rate of 2% simple interest.
(3) Find the amount to be paid if Charles borrowed a sum of $5900 at 9% simple interest for 7 years.
(4) Charles took a loan of $5800 at the rate of 10% simple interest per annum. If he paid an amount of $10440 to clear the loan, then find the time period of the loan.
(5) Calculate the amount due after 9 years if Susan borrowed a sum of $5650 at a rate of 8% simple interest.
(6) In how much time a principal of $3100 will amount to $3565 at a simple interest of 3% per annum?
(7) Calculate the amount due if Thomas borrowed a sum of $3800 at 8% simple interest for 3 years.
(8) In how much time a principal of $3150 will amount to $3276 at a simple interest of 2% per annum?
(9) How much loan did Amanda borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $8580 to clear it?
(10) Anthony took a loan of $6600 at the rate of 8% simple interest per annum. If he paid an amount of $9768 to clear the loan, then find the time period of the loan.