Question:
Calculate the amount due if John borrowed a sum of $3200 at 3% simple interest for 4 years.
Correct Answer
$3584
Solution And Explanation
Solution
Given,
Principal (P) = $3200
Rate of Simple Interest (SI) = 3%
Time (t) = 4 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) = $3200 × 3% × 4
= $3200 ×3/100 × 4
= 3200 × 3 × 4/100
= 9600 × 4/100
= 38400/100
= $384
Thus, Simple Interest = $384
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 = $3200 + $384
= $3584
Thus, Amount to be paid = $3584 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 = $3200
Rate of Simple Interest (SI) or (R) = 3%
And, Time (t) = 4 years
Thus, Amount (A)
= $3200 + ($3200 × 3% × 4)
= $3200 + ($3200 ×3/100 × 4)
= $3200 + (3200 × 3 × 4/100)
= $3200 + (9600 × 4/100)
= $3200 + (38400/100)
= $3200 + $384 = $3584
Thus, Amount (A) to be paid = $3584 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 $3200, the simple interest in 1 year
= 3/100 × 3200
= 3 × 3200/100
= 9600/100 = $96
Thus, simple interest for 1 year = $96
Therefore, simple interest for 4 years
= Simple interest for 1 year × 4
= $96 × 4 = $384
Thus, Simple Interest (SI) = $384
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3200 + $384
= $3584
Thus, Amount to be paid = $3584 Answer
Similar Questions
(1) Find the amount to be paid if Christopher borrowed a sum of $6000 at 4% simple interest for 7 years.
(2) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 8% simple interest for 7 years.
(3) What amount does James have to pay after 6 years if he takes a loan of $3000 at 5% simple interest?
(4) If Emily paid $5510 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.
(5) Calculate the amount due after 9 years if Jennifer borrowed a sum of $5250 at a rate of 8% simple interest.
(6) Matthew took a loan of $6400 at the rate of 9% simple interest per annum. If he paid an amount of $9856 to clear the loan, then find the time period of the loan.
(7) What amount will be due after 2 years if James borrowed a sum of $3000 at a 5% simple interest?
(8) Susan took a loan of $5300 at the rate of 6% simple interest per annum. If he paid an amount of $7208 to clear the loan, then find the time period of the loan.
(9) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 9% simple interest for 8 years.
(10) Joseph took a loan of $5400 at the rate of 9% simple interest per annum. If he paid an amount of $9288 to clear the loan, then find the time period of the loan.