Question:
Calculate the amount due if Charles borrowed a sum of $3900 at 4% simple interest for 3 years.
Correct Answer
$4368
Solution And Explanation
Solution
Given,
Principal (P) = $3900
Rate of Simple Interest (SI) = 4%
Time (t) = 3 years
Thus, Amount (A) = ?
The Rate of Interest is always calculated per annum, i.e. per year.
Thus, here 4% simple interest means, Rate of Simple Interest (SI) is 4% 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 × 4% × 3
= $3900 ×4/100 × 3
= 3900 × 4 × 3/100
= 15600 × 3/100
= 46800/100
= $468
Thus, Simple Interest = $468
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 + $468
= $4368
Thus, Amount to be paid = $4368 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) = 4%
And, Time (t) = 3 years
Thus, Amount (A)
= $3900 + ($3900 × 4% × 3)
= $3900 + ($3900 ×4/100 × 3)
= $3900 + (3900 × 4 × 3/100)
= $3900 + (15600 × 3/100)
= $3900 + (46800/100)
= $3900 + $468 = $4368
Thus, Amount (A) to be paid = $4368 Answer
Method (3) Unitary Method
Calculation of Amount using Unitary Method
Calculation of Interest using Unitary Method
Here, given Rate of Simple Interest = 4%
This, means, $4 per $100 per year
∵ For $100, the simple interest for 1 year = $4
∴ For $1, the simple interest for 1 year = 4/100
∴ For $3900, the simple interest in 1 year
= 4/100 × 3900
= 4 × 3900/100
= 15600/100 = $156
Thus, simple interest for 1 year = $156
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $156 × 3 = $468
Thus, Simple Interest (SI) = $468
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3900 + $468
= $4368
Thus, Amount to be paid = $4368 Answer
Similar Questions
(1) Calculate the amount due after 9 years if Linda borrowed a sum of $5350 at a rate of 8% simple interest.
(2) Linda had to pay $3752 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.
(3) Patricia took a loan of $4300 at the rate of 10% simple interest per annum. If he paid an amount of $8170 to clear the loan, then find the time period of the loan.
(4) If Patricia borrowed $3150 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 years.
(5) Calculate the amount due after 9 years if Jennifer borrowed a sum of $5250 at a rate of 5% simple interest.
(6) How much loan did Melissa borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $8820 to clear it?
(7) Find the amount to be paid if Joseph borrowed a sum of $5700 at 3% simple interest for 8 years.
(8) Susan took a loan of $5300 at the rate of 10% simple interest per annum. If he paid an amount of $9540 to clear the loan, then find the time period of the loan.
(9) How much loan did Dorothy borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $9062.5 to clear it?
(10) Calculate the amount due after 9 years if Richard borrowed a sum of $5600 at a rate of 6% simple interest.