Question:
Calculate the amount due if James borrowed a sum of $3000 at 3% simple interest for 3 years.
Correct Answer
$3270
Solution And Explanation
Solution
Given,
Principal (P) = $3000
Rate of Simple Interest (SI) = 3%
Time (t) = 3 years
Thus, Amount (A) = ?
The Rate of Interest is always calculated per annum, i.e. per year.
Thus, here 3% simple interest means, Rate of Simple Interest (SI) is 3% 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) = $3000 × 3% × 3
= $3000 ×3/100 × 3
= 3000 × 3 × 3/100
= 9000 × 3/100
= 27000/100
= $270
Thus, Simple Interest = $270
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 = $3000 + $270
= $3270
Thus, Amount to be paid = $3270 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 = $3000
Rate of Simple Interest (SI) or (R) = 3%
And, Time (t) = 3 years
Thus, Amount (A)
= $3000 + ($3000 × 3% × 3)
= $3000 + ($3000 ×3/100 × 3)
= $3000 + (3000 × 3 × 3/100)
= $3000 + (9000 × 3/100)
= $3000 + (27000/100)
= $3000 + $270 = $3270
Thus, Amount (A) to be paid = $3270 Answer
Method (3) Unitary Method
Calculation of Amount using Unitary Method
Calculation of Interest using Unitary Method
Here, given Rate of Simple Interest = 3%
This, means, $3 per $100 per year
∵ For $100, the simple interest for 1 year = $3
∴ For $1, the simple interest for 1 year = 3/100
∴ For $3000, the simple interest in 1 year
= 3/100 × 3000
= 3 × 3000/100
= 9000/100 = $90
Thus, simple interest for 1 year = $90
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $90 × 3 = $270
Thus, Simple Interest (SI) = $270
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3000 + $270
= $3270
Thus, Amount to be paid = $3270 Answer
Similar Questions
(1) Calculate the amount due if Karen borrowed a sum of $3950 at 7% simple interest for 3 years.
(2) How much loan did William borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $6325 to clear it?
(3) What amount does Susan have to pay after 6 years if he takes a loan of $3650 at 8% simple interest?
(4) What amount will be due after 2 years if Donald borrowed a sum of $3750 at a 9% simple interest?
(5) What amount does Robert have to pay after 5 years if he takes a loan of $3100 at 5% simple interest?
(6) If Elizabeth paid $4140 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.
(7) Find the amount to be paid if Jessica borrowed a sum of $5750 at 8% simple interest for 8 years.
(8) What amount does David have to pay after 6 years if he takes a loan of $3400 at 5% simple interest?
(9) Find the amount to be paid if Karen borrowed a sum of $5950 at 10% simple interest for 8 years.
(10) Calculate the amount due if Charles borrowed a sum of $3900 at 4% simple interest for 3 years.