Question:
Calculate the amount due after 9 years if David borrowed a sum of $5400 at a rate of 2% simple interest.
Correct Answer
$6372
Solution And Explanation
Solution
Given,
Principal (P) = $5400
Rate of Simple Interest (SI) = 2%
Time (t) = 9 years
Thus, Amount (A) = ?
The Rate of Interest is always calculated per annum, i.e. per year.
Thus, here 2% simple interest means, Rate of Simple Interest (SI) is 2% 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) = $5400 × 2% × 9
= $5400 ×2/100 × 9
= 5400 × 2 × 9/100
= 10800 × 9/100
= 97200/100
= $972
Thus, Simple Interest = $972
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 = $5400 + $972
= $6372
Thus, Amount to be paid = $6372 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 = $5400
Rate of Simple Interest (SI) or (R) = 2%
And, Time (t) = 9 years
Thus, Amount (A)
= $5400 + ($5400 × 2% × 9)
= $5400 + ($5400 ×2/100 × 9)
= $5400 + (5400 × 2 × 9/100)
= $5400 + (10800 × 9/100)
= $5400 + (97200/100)
= $5400 + $972 = $6372
Thus, Amount (A) to be paid = $6372 Answer
Method (3) Unitary Method
Calculation of Amount using Unitary Method
Calculation of Interest using Unitary Method
Here, given Rate of Simple Interest = 2%
This, means, $2 per $100 per year
∵ For $100, the simple interest for 1 year = $2
∴ For $1, the simple interest for 1 year = 2/100
∴ For $5400, the simple interest in 1 year
= 2/100 × 5400
= 2 × 5400/100
= 10800/100 = $108
Thus, simple interest for 1 year = $108
Therefore, simple interest for 9 years
= Simple interest for 1 year × 9
= $108 × 9 = $972
Thus, Simple Interest (SI) = $972
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $5400 + $972
= $6372
Thus, Amount to be paid = $6372 Answer
Similar Questions
(1) Calculate the amount due after 9 years if Susan borrowed a sum of $5650 at a rate of 5% simple interest.
(2) What amount will be due after 2 years if John borrowed a sum of $3100 at a 7% simple interest?
(3) Calculate the amount due after 9 years if Robert borrowed a sum of $5100 at a rate of 6% simple interest.
(4) Mary took a loan of $4100 at the rate of 6% simple interest per annum. If he paid an amount of $5822 to clear the loan, then find the time period of the loan.
(5) What amount will be due after 2 years if Mark borrowed a sum of $3700 at a 4% simple interest?
(6) In how much time a principal of $3150 will amount to $3622.5 at a simple interest of 5% per annum?
(7) Anthony took a loan of $6600 at the rate of 10% simple interest per annum. If he paid an amount of $10560 to clear the loan, then find the time period of the loan.
(8) What amount does Mary have to pay after 5 years if he takes a loan of $3050 at 10% simple interest?
(9) Betty took a loan of $6500 at the rate of 7% simple interest per annum. If he paid an amount of $11050 to clear the loan, then find the time period of the loan.
(10) Calculate the amount due after 9 years if John borrowed a sum of $5200 at a rate of 8% simple interest.