Question:
Calculate the amount due if Richard borrowed a sum of $3600 at 5% simple interest for 3 years.
Correct Answer
$4140
Solution And Explanation
Solution
Given,
Principal (P) = $3600
Rate of Simple Interest (SI) = 5%
Time (t) = 3 years
Thus, Amount (A) = ?
The Rate of Interest is always calculated per annum, i.e. per year.
Thus, here 5% simple interest means, Rate of Simple Interest (SI) is 5% 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 × 5% × 3
= $3600 ×5/100 × 3
= 3600 × 5 × 3/100
= 18000 × 3/100
= 54000/100
= $540
Thus, Simple Interest = $540
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 + $540
= $4140
Thus, Amount to be paid = $4140 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) = 5%
And, Time (t) = 3 years
Thus, Amount (A)
= $3600 + ($3600 × 5% × 3)
= $3600 + ($3600 ×5/100 × 3)
= $3600 + (3600 × 5 × 3/100)
= $3600 + (18000 × 3/100)
= $3600 + (54000/100)
= $3600 + $540 = $4140
Thus, Amount (A) to be paid = $4140 Answer
Method (3) Unitary Method
Calculation of Amount using Unitary Method
Calculation of Interest using Unitary Method
Here, given Rate of Simple Interest = 5%
This, means, $5 per $100 per year
∵ For $100, the simple interest for 1 year = $5
∴ For $1, the simple interest for 1 year = 5/100
∴ For $3600, the simple interest in 1 year
= 5/100 × 3600
= 5 × 3600/100
= 18000/100 = $180
Thus, simple interest for 1 year = $180
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $180 × 3 = $540
Thus, Simple Interest (SI) = $540
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3600 + $540
= $4140
Thus, Amount to be paid = $4140 Answer
Similar Questions
(1) Find the amount to be paid if Charles borrowed a sum of $5900 at 8% simple interest for 7 years.
(2) Calculate the amount due after 9 years if Michael borrowed a sum of $5300 at a rate of 4% simple interest.
(3) Joseph took a loan of $5400 at the rate of 7% simple interest per annum. If he paid an amount of $8424 to clear the loan, then find the time period of the loan.
(4) Calculate the amount due if Jessica borrowed a sum of $3750 at 8% simple interest for 3 years.
(5) Calculate the amount due after 9 years if Thomas borrowed a sum of $5800 at a rate of 10% simple interest.
(6) Calculate the amount due if Jessica borrowed a sum of $3750 at 5% simple interest for 4 years.
(7) Find the amount to be paid if Joseph borrowed a sum of $5700 at 7% simple interest for 8 years.
(8) Barbara took a loan of $5100 at the rate of 7% simple interest per annum. If he paid an amount of $7242 to clear the loan, then find the time period of the loan.
(9) Daniel took a loan of $6200 at the rate of 8% simple interest per annum. If he paid an amount of $9672 to clear the loan, then find the time period of the loan.
(10) Sandra took a loan of $6900 at the rate of 10% simple interest per annum. If he paid an amount of $11040 to clear the loan, then find the time period of the loan.