Question:
Calculate the amount due after 9 years if Robert borrowed a sum of $5100 at a rate of 4% simple interest.
Correct Answer
$6936
Solution And Explanation
Solution
Given,
Principal (P) = $5100
Rate of Simple Interest (SI) = 4%
Time (t) = 9 years
Thus, Amount (A) = ?
The Rate of Interest is always calculated per annum, i.e. per year.
Thus, here 4% simple interest means, Rate of Simple Interest (SI) is 4% 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) = $5100 × 4% × 9
= $5100 ×4/100 × 9
= 5100 × 4 × 9/100
= 20400 × 9/100
= 183600/100
= $1836
Thus, Simple Interest = $1836
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 = $5100 + $1836
= $6936
Thus, Amount to be paid = $6936 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 = $5100
Rate of Simple Interest (SI) or (R) = 4%
And, Time (t) = 9 years
Thus, Amount (A)
= $5100 + ($5100 × 4% × 9)
= $5100 + ($5100 ×4/100 × 9)
= $5100 + (5100 × 4 × 9/100)
= $5100 + (20400 × 9/100)
= $5100 + (183600/100)
= $5100 + $1836 = $6936
Thus, Amount (A) to be paid = $6936 Answer
Method (3) Unitary Method
Calculation of Amount using Unitary Method
Calculation of Interest using Unitary Method
Here, given Rate of Simple Interest = 4%
This, means, $4 per $100 per year
∵ For $100, the simple interest for 1 year = $4
∴ For $1, the simple interest for 1 year = 4/100
∴ For $5100, the simple interest in 1 year
= 4/100 × 5100
= 4 × 5100/100
= 20400/100 = $204
Thus, simple interest for 1 year = $204
Therefore, simple interest for 9 years
= Simple interest for 1 year × 9
= $204 × 9 = $1836
Thus, Simple Interest (SI) = $1836
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $5100 + $1836
= $6936
Thus, Amount to be paid = $6936 Answer
Similar Questions
(1) If Mary paid $3416 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.
(2) Nancy took a loan of $6300 at the rate of 7% simple interest per annum. If he paid an amount of $8946 to clear the loan, then find the time period of the loan.
(3) Daniel had to pay $4715 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.
(4) Calculate the amount due if Jennifer borrowed a sum of $3250 at 7% simple interest for 3 years.
(5) What amount does Sarah have to pay after 5 years if he takes a loan of $3850 at 2% simple interest?
(6) How much loan did Kevin borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $8520 to clear it?
(7) Susan had to pay $4088 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.
(8) Jennifer had to pay $3445 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.
(9) What amount will be due after 2 years if Steven borrowed a sum of $3800 at a 5% simple interest?
(10) Calculate the amount due if Mary borrowed a sum of $3050 at 4% simple interest for 3 years.