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) Calculate the amount due after 9 years if Barbara borrowed a sum of $5550 at a rate of 2% simple interest.
(2) 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?
(3) Find the amount to be paid if William borrowed a sum of $5500 at 8% simple interest for 7 years.
(4) What amount will be due after 2 years if David borrowed a sum of $3200 at a 9% simple interest?
(5) In how much time a principal of $3050 will amount to $3812.5 at a simple interest of 5% per annum?
(6) Calculate the amount due after 10 years if Jessica borrowed a sum of $5750 at a rate of 6% simple interest.
(7) Lisa took a loan of $6100 at the rate of 7% simple interest per annum. If he paid an amount of $9089 to clear the loan, then find the time period of the loan.
(8) What amount will be due after 2 years if Donald borrowed a sum of $3750 at a 10% simple interest?
(9) Nancy took a loan of $6300 at the rate of 8% simple interest per annum. If he paid an amount of $11340 to clear the loan, then find the time period of the loan.
(10) What amount will be due after 2 years if Joseph borrowed a sum of $3350 at a 8% simple interest?