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) What amount does Mary have to pay after 6 years if he takes a loan of $3050 at 4% simple interest?
(2) Find the amount to be paid if William borrowed a sum of $5500 at 8% simple interest for 7 years.
(3) Calculate the amount due if Susan borrowed a sum of $3650 at 8% simple interest for 3 years.
(4) What amount does Robert have to pay after 5 years if he takes a loan of $3100 at 3% simple interest?
(5) Jessica took a loan of $5500 at the rate of 7% simple interest per annum. If he paid an amount of $7810 to clear the loan, then find the time period of the loan.
(6) How much loan did Jennifer borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $6562.5 to clear it?
(7) James took a loan of $4000 at the rate of 7% simple interest per annum. If he paid an amount of $6520 to clear the loan, then find the time period of the loan.
(8) Calculate the amount due after 9 years if Elizabeth borrowed a sum of $5450 at a rate of 3% simple interest.
(9) How much loan did Brian borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $8280 to clear it?
(10) Daniel took a loan of $6200 at the rate of 7% simple interest per annum. If he paid an amount of $8804 to clear the loan, then find the time period of the loan.