Question:
Calculate the amount due if Charles borrowed a sum of $3900 at 9% simple interest for 3 years.
Correct Answer
$4953
Solution And Explanation
Solution
Given,
Principal (P) = $3900
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) = $3900 × 9% × 3
= $3900 ×9/100 × 3
= 3900 × 9 × 3/100
= 35100 × 3/100
= 105300/100
= $1053
Thus, Simple Interest = $1053
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 = $3900 + $1053
= $4953
Thus, Amount to be paid = $4953 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 = $3900
Rate of Simple Interest (SI) or (R) = 9%
And, Time (t) = 3 years
Thus, Amount (A)
= $3900 + ($3900 × 9% × 3)
= $3900 + ($3900 ×9/100 × 3)
= $3900 + (3900 × 9 × 3/100)
= $3900 + (35100 × 3/100)
= $3900 + (105300/100)
= $3900 + $1053 = $4953
Thus, Amount (A) to be paid = $4953 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 $3900, the simple interest in 1 year
= 9/100 × 3900
= 9 × 3900/100
= 35100/100 = $351
Thus, simple interest for 1 year = $351
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $351 × 3 = $1053
Thus, Simple Interest (SI) = $1053
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3900 + $1053
= $4953
Thus, Amount to be paid = $4953 Answer
Similar Questions
(1) Kimberly had to pay $5068.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 3% then find the sum borrowed.
(2) If Sarah paid $4158 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.
(3) Calculate the amount due if David borrowed a sum of $3400 at 2% simple interest for 3 years.
(4) Calculate the amount due after 10 years if Jessica borrowed a sum of $5750 at a rate of 9% simple interest.
(5) Calculate the amount due if Christopher borrowed a sum of $4000 at 10% simple interest for 3 years.
(6) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 5% simple interest for 8 years.
(7) Calculate the amount due after 10 years if Christopher borrowed a sum of $6000 at a rate of 7% simple interest.
(8) Richard took a loan of $5200 at the rate of 6% simple interest per annum. If he paid an amount of $7696 to clear the loan, then find the time period of the loan.
(9) If Donna paid $5238 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.
(10) What amount does Christopher have to pay after 5 years if he takes a loan of $4000 at 10% simple interest?