Question:
Calculate the amount due if Karen borrowed a sum of $3950 at 3% simple interest for 4 years.
Correct Answer
$4424
Solution And Explanation
Solution
Given,
Principal (P) = $3950
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) = $3950 × 3% × 4
= $3950 ×3/100 × 4
= 3950 × 3 × 4/100
= 11850 × 4/100
= 47400/100
= $474
Thus, Simple Interest = $474
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 = $3950 + $474
= $4424
Thus, Amount to be paid = $4424 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 = $3950
Rate of Simple Interest (SI) or (R) = 3%
And, Time (t) = 4 years
Thus, Amount (A)
= $3950 + ($3950 × 3% × 4)
= $3950 + ($3950 ×3/100 × 4)
= $3950 + (3950 × 3 × 4/100)
= $3950 + (11850 × 4/100)
= $3950 + (47400/100)
= $3950 + $474 = $4424
Thus, Amount (A) to be paid = $4424 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 $3950, the simple interest in 1 year
= 3/100 × 3950
= 3 × 3950/100
= 11850/100 = $118.5
Thus, simple interest for 1 year = $118.5
Therefore, simple interest for 4 years
= Simple interest for 1 year × 4
= $118.5 × 4 = $474
Thus, Simple Interest (SI) = $474
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3950 + $474
= $4424
Thus, Amount to be paid = $4424 Answer
Similar Questions
(1) Calculate the amount due after 10 years if Patricia borrowed a sum of $5150 at a rate of 4% simple interest.
(2) Calculate the amount due if David borrowed a sum of $3400 at 8% simple interest for 4 years.
(3) Find the amount to be paid if Karen borrowed a sum of $5950 at 5% simple interest for 7 years.
(4) Find the amount to be paid if Christopher borrowed a sum of $6000 at 6% simple interest for 8 years.
(5) Calculate the amount due if James borrowed a sum of $3000 at 5% simple interest for 4 years.
(6) Find the amount to be paid if Richard borrowed a sum of $5600 at 3% simple interest for 7 years.
(7) Barbara took a loan of $5100 at the rate of 9% simple interest per annum. If he paid an amount of $7854 to clear the loan, then find the time period of the loan.
(8) Calculate the amount due after 10 years if Michael borrowed a sum of $5300 at a rate of 8% simple interest.
(9) Sandra took a loan of $6900 at the rate of 8% simple interest per annum. If he paid an amount of $12420 to clear the loan, then find the time period of the loan.
(10) Lisa took a loan of $6100 at the rate of 10% simple interest per annum. If he paid an amount of $10370 to clear the loan, then find the time period of the loan.