Question:
Calculate the amount due if Susan borrowed a sum of $3650 at 9% simple interest for 4 years.
Correct Answer
$4964
Solution And Explanation
Solution
Given,
Principal (P) = $3650
Rate of Simple Interest (SI) = 9%
Time (t) = 4 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) = $3650 × 9% × 4
= $3650 ×9/100 × 4
= 3650 × 9 × 4/100
= 32850 × 4/100
= 131400/100
= $1314
Thus, Simple Interest = $1314
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 = $3650 + $1314
= $4964
Thus, Amount to be paid = $4964 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 = $3650
Rate of Simple Interest (SI) or (R) = 9%
And, Time (t) = 4 years
Thus, Amount (A)
= $3650 + ($3650 × 9% × 4)
= $3650 + ($3650 ×9/100 × 4)
= $3650 + (3650 × 9 × 4/100)
= $3650 + (32850 × 4/100)
= $3650 + (131400/100)
= $3650 + $1314 = $4964
Thus, Amount (A) to be paid = $4964 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 $3650, the simple interest in 1 year
= 9/100 × 3650
= 9 × 3650/100
= 32850/100 = $328.5
Thus, simple interest for 1 year = $328.5
Therefore, simple interest for 4 years
= Simple interest for 1 year × 4
= $328.5 × 4 = $1314
Thus, Simple Interest (SI) = $1314
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3650 + $1314
= $4964
Thus, Amount to be paid = $4964 Answer
Similar Questions
(1) Calculate the amount due after 9 years if Susan borrowed a sum of $5650 at a rate of 9% simple interest.
(2) In how much time a principal of $3150 will amount to $3276 at a simple interest of 2% per annum?
(3) Calculate the amount due after 9 years if Thomas borrowed a sum of $5800 at a rate of 3% simple interest.
(4) What amount does Mary have to pay after 5 years if he takes a loan of $3050 at 5% simple interest?
(5) What amount does David have to pay after 6 years if he takes a loan of $3400 at 5% simple interest?
(6) Anthony took a loan of $6600 at the rate of 8% simple interest per annum. If he paid an amount of $11880 to clear the loan, then find the time period of the loan.
(7) What amount does John have to pay after 6 years if he takes a loan of $3200 at 7% simple interest?
(8) Donald took a loan of $7000 at the rate of 6% simple interest per annum. If he paid an amount of $9940 to clear the loan, then find the time period of the loan.
(9) Mark took a loan of $6800 at the rate of 6% simple interest per annum. If he paid an amount of $9248 to clear the loan, then find the time period of the loan.
(10) Find the amount to be paid if Mary borrowed a sum of $5050 at 4% simple interest for 8 years.