Question:
What amount will be due after 2 years if Andrew borrowed a sum of $3900 at a 9% simple interest?
Correct Answer
$4602
Solution And Explanation
Solution
Given,
Principal (P) = $3900
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) = $3900 × 9% × 2
= $3900 ×9/100 × 2
= 3900 × 9 × 2/100
= 35100 × 2/100
= 70200/100
= $702
Thus, Simple Interest = $702
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 = $3900 + $702
= $4602
Thus, Amount to be paid = $4602 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 = $3900
Rate of Simple Interest (SI) or (R) = 9%
And, Time (t) = 2 years
Thus, Amount (A)
= $3900 + ($3900 × 9% × 2)
= $3900 + ($3900 ×9/100 × 2)
= $3900 + (3900 × 9 × 2/100)
= $3900 + (35100 × 2/100)
= $3900 + (70200/100)
= $3900 + $702 = $4602
Thus, Amount (A) to be paid = $4602 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 $3900, the simple interest in 1 year
= 9/100 × 3900
= 9 × 3900/100
= 35100/100 = $351
Thus, simple interest for 1 year = $351
Therefore, simple interest for 2 years
= Simple interest for 1 year × 2
= $351 × 2 = $702
Thus, Simple Interest (SI) = $702
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3900 + $702
= $4602
Thus, Amount to be paid = $4602 Answer
Similar Questions
(1) Jessica took a loan of $5500 at the rate of 8% simple interest per annum. If he paid an amount of $9460 to clear the loan, then find the time period of the loan.
(2) Charles took a loan of $5800 at the rate of 8% simple interest per annum. If he paid an amount of $9976 to clear the loan, then find the time period of the loan.
(3) David took a loan of $4800 at the rate of 6% simple interest per annum. If he paid an amount of $7392 to clear the loan, then find the time period of the loan.
(4) What amount does Elizabeth have to pay after 6 years if he takes a loan of $3450 at 5% simple interest?
(5) Find the amount to be paid if Susan borrowed a sum of $5650 at 3% simple interest for 7 years.
(6) Calculate the amount due if Richard borrowed a sum of $3600 at 3% simple interest for 3 years.
(7) Mary took a loan of $4100 at the rate of 9% simple interest per annum. If he paid an amount of $7052 to clear the loan, then find the time period of the loan.
(8) What amount does Karen have to pay after 5 years if he takes a loan of $3950 at 9% simple interest?
(9) Karen took a loan of $5900 at the rate of 9% simple interest per annum. If he paid an amount of $11210 to clear the loan, then find the time period of the loan.
(10) Calculate the amount due after 9 years if James borrowed a sum of $5000 at a rate of 3% simple interest.