Question:
What amount will be due after 2 years if Matthew borrowed a sum of $3600 at a 9% simple interest?
Correct Answer
$4248
Solution And Explanation
Solution
Given,
Principal (P) = $3600
Rate of Simple Interest (SI) = 9%
Time (t) = 2 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) = $3600 × 9% × 2
= $3600 ×9/100 × 2
= 3600 × 9 × 2/100
= 32400 × 2/100
= 64800/100
= $648
Thus, Simple Interest = $648
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 + $648
= $4248
Thus, Amount to be paid = $4248 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) = 9%
And, Time (t) = 2 years
Thus, Amount (A)
= $3600 + ($3600 × 9% × 2)
= $3600 + ($3600 ×9/100 × 2)
= $3600 + (3600 × 9 × 2/100)
= $3600 + (32400 × 2/100)
= $3600 + (64800/100)
= $3600 + $648 = $4248
Thus, Amount (A) to be paid = $4248 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 $3600, the simple interest in 1 year
= 9/100 × 3600
= 9 × 3600/100
= 32400/100 = $324
Thus, simple interest for 1 year = $324
Therefore, simple interest for 2 years
= Simple interest for 1 year × 2
= $324 × 2 = $648
Thus, Simple Interest (SI) = $648
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3600 + $648
= $4248
Thus, Amount to be paid = $4248 Answer
Similar Questions
(1) How much loan did Kenneth borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $8050 to clear it?
(2) 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.
(3) How much loan did Brian borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $7920 to clear it?
(4) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 6% simple interest for 7 years.
(5) Calculate the amount due after 9 years if Barbara borrowed a sum of $5550 at a rate of 4% simple interest.
(6) Find the amount to be paid if Linda borrowed a sum of $5350 at 10% simple interest for 8 years.
(7) Calculate the amount due after 10 years if Karen borrowed a sum of $5950 at a rate of 10% simple interest.
(8) What amount does Richard have to pay after 6 years if he takes a loan of $3600 at 4% simple interest?
(9) In how much time a principal of $3000 will amount to $3120 at a simple interest of 2% per annum?
(10) What amount does Thomas have to pay after 6 years if he takes a loan of $3800 at 9% simple interest?