Question:
What amount will be due after 2 years if Christopher borrowed a sum of $3500 at a 9% simple interest?
Correct Answer
$4130
Solution And Explanation
Solution
Given,
Principal (P) = $3500
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) = $3500 × 9% × 2
= $3500 ×9/100 × 2
= 3500 × 9 × 2/100
= 31500 × 2/100
= 63000/100
= $630
Thus, Simple Interest = $630
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 = $3500 + $630
= $4130
Thus, Amount to be paid = $4130 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 = $3500
Rate of Simple Interest (SI) or (R) = 9%
And, Time (t) = 2 years
Thus, Amount (A)
= $3500 + ($3500 × 9% × 2)
= $3500 + ($3500 ×9/100 × 2)
= $3500 + (3500 × 9 × 2/100)
= $3500 + (31500 × 2/100)
= $3500 + (63000/100)
= $3500 + $630 = $4130
Thus, Amount (A) to be paid = $4130 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 $3500, the simple interest in 1 year
= 9/100 × 3500
= 9 × 3500/100
= 31500/100 = $315
Thus, simple interest for 1 year = $315
Therefore, simple interest for 2 years
= Simple interest for 1 year × 2
= $315 × 2 = $630
Thus, Simple Interest (SI) = $630
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3500 + $630
= $4130
Thus, Amount to be paid = $4130 Answer
Similar Questions
(1) If Daniel paid $4920 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.
(2) Susan took a loan of $5300 at the rate of 6% simple interest per annum. If he paid an amount of $7526 to clear the loan, then find the time period of the loan.
(3) Donald took a loan of $7000 at the rate of 8% simple interest per annum. If he paid an amount of $11480 to clear the loan, then find the time period of the loan.
(4) What amount does Linda have to pay after 6 years if he takes a loan of $3350 at 3% simple interest?
(5) Christopher took a loan of $6000 at the rate of 9% simple interest per annum. If he paid an amount of $9780 to clear the loan, then find the time period of the loan.
(6) In how much time a principal of $3000 will amount to $3240 at a simple interest of 4% per annum?
(7) What amount does Charles have to pay after 6 years if he takes a loan of $3900 at 9% simple interest?
(8) Calculate the amount due after 10 years if Jennifer borrowed a sum of $5250 at a rate of 7% simple interest.
(9) In how much time a principal of $3100 will amount to $3286 at a simple interest of 2% per annum?
(10) In how much time a principal of $3200 will amount to $3712 at a simple interest of 4% per annum?