Question:
Calculate the amount due if Patricia borrowed a sum of $3150 at 9% simple interest for 4 years.
Correct Answer
$4284
Solution And Explanation
Solution
Given,
Principal (P) = $3150
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) = $3150 × 9% × 4
= $3150 ×9/100 × 4
= 3150 × 9 × 4/100
= 28350 × 4/100
= 113400/100
= $1134
Thus, Simple Interest = $1134
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 = $3150 + $1134
= $4284
Thus, Amount to be paid = $4284 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 = $3150
Rate of Simple Interest (SI) or (R) = 9%
And, Time (t) = 4 years
Thus, Amount (A)
= $3150 + ($3150 × 9% × 4)
= $3150 + ($3150 ×9/100 × 4)
= $3150 + (3150 × 9 × 4/100)
= $3150 + (28350 × 4/100)
= $3150 + (113400/100)
= $3150 + $1134 = $4284
Thus, Amount (A) to be paid = $4284 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 $3150, the simple interest in 1 year
= 9/100 × 3150
= 9 × 3150/100
= 28350/100 = $283.5
Thus, simple interest for 1 year = $283.5
Therefore, simple interest for 4 years
= Simple interest for 1 year × 4
= $283.5 × 4 = $1134
Thus, Simple Interest (SI) = $1134
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3150 + $1134
= $4284
Thus, Amount to be paid = $4284 Answer
Similar Questions
(1) How much loan did Karen borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $6842.5 to clear it?
(2) Calculate the amount due if Susan borrowed a sum of $3650 at 4% simple interest for 4 years.
(3) Calculate the amount due after 9 years if James borrowed a sum of $5000 at a rate of 2% simple interest.
(4) Find the amount to be paid if Mary borrowed a sum of $5050 at 8% simple interest for 7 years.
(5) Calculate the amount due after 9 years if John borrowed a sum of $5200 at a rate of 2% simple interest.
(6) Find the amount to be paid if Linda borrowed a sum of $5350 at 7% simple interest for 7 years.
(7) What amount will be due after 2 years if Donald borrowed a sum of $3750 at a 5% simple interest?
(8) How much loan did Anthony borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $7875 to clear it?
(9) Find the amount to be paid if Robert borrowed a sum of $5100 at 3% simple interest for 7 years.
(10) Find the amount to be paid if Robert borrowed a sum of $5100 at 10% simple interest for 8 years.