Question:
Calculate the amount due if James borrowed a sum of $3000 at 9% simple interest for 3 years.
Correct Answer
$3810
Solution And Explanation
Solution
Given,
Principal (P) = $3000
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) = $3000 × 9% × 3
= $3000 ×9/100 × 3
= 3000 × 9 × 3/100
= 27000 × 3/100
= 81000/100
= $810
Thus, Simple Interest = $810
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 = $3000 + $810
= $3810
Thus, Amount to be paid = $3810 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 = $3000
Rate of Simple Interest (SI) or (R) = 9%
And, Time (t) = 3 years
Thus, Amount (A)
= $3000 + ($3000 × 9% × 3)
= $3000 + ($3000 ×9/100 × 3)
= $3000 + (3000 × 9 × 3/100)
= $3000 + (27000 × 3/100)
= $3000 + (81000/100)
= $3000 + $810 = $3810
Thus, Amount (A) to be paid = $3810 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 $3000, the simple interest in 1 year
= 9/100 × 3000
= 9 × 3000/100
= 27000/100 = $270
Thus, simple interest for 1 year = $270
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $270 × 3 = $810
Thus, Simple Interest (SI) = $810
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3000 + $810
= $3810
Thus, Amount to be paid = $3810 Answer
Similar Questions
(1) Linda took a loan of $4700 at the rate of 10% simple interest per annum. If he paid an amount of $7520 to clear the loan, then find the time period of the loan.
(2) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 7% simple interest for 7 years.
(3) Calculate the amount due if Robert borrowed a sum of $3100 at 2% simple interest for 3 years.
(4) Find the amount to be paid if David borrowed a sum of $5400 at 7% simple interest for 7 years.
(5) Karen took a loan of $5900 at the rate of 9% simple interest per annum. If he paid an amount of $11210 to clear the loan, then find the time period of the loan.
(6) Mark took a loan of $6800 at the rate of 9% simple interest per annum. If he paid an amount of $12920 to clear the loan, then find the time period of the loan.
(7) Margaret took a loan of $6700 at the rate of 6% simple interest per annum. If he paid an amount of $9112 to clear the loan, then find the time period of the loan.
(8) Find the amount to be paid if Patricia borrowed a sum of $5150 at 9% simple interest for 7 years.
(9) Richard took a loan of $5200 at the rate of 7% simple interest per annum. If he paid an amount of $8112 to clear the loan, then find the time period of the loan.
(10) Christopher took a loan of $6000 at the rate of 7% simple interest per annum. If he paid an amount of $10200 to clear the loan, then find the time period of the loan.