Question:
What amount will be due after 2 years if Andrew borrowed a sum of $3900 at a 6% simple interest?
Correct Answer
$4368
Solution And Explanation
Solution
Given,
Principal (P) = $3900
Rate of Simple Interest (SI) = 6%
Time (t) = 2 years
Thus, Amount (A) = ?
The Rate of Interest is always calculated per annum, i.e. per year.
Thus, here 6% simple interest means, Rate of Simple Interest (SI) is 6% 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 × 6% × 2
= $3900 ×6/100 × 2
= 3900 × 6 × 2/100
= 23400 × 2/100
= 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) = 6%
And, Time (t) = 2 years
Thus, Amount (A)
= $3900 + ($3900 × 6% × 2)
= $3900 + ($3900 ×6/100 × 2)
= $3900 + (3900 × 6 × 2/100)
= $3900 + (23400 × 2/100)
= $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 = 6%
This, means, $6 per $100 per year
∵ For $100, the simple interest for 1 year = $6
∴ For $1, the simple interest for 1 year = 6/100
∴ For $3900, the simple interest in 1 year
= 6/100 × 3900
= 6 × 3900/100
= 23400/100 = $234
Thus, simple interest for 1 year = $234
Therefore, simple interest for 2 years
= Simple interest for 1 year × 2
= $234 × 2 = $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) What amount will be due after 2 years if Richard borrowed a sum of $3300 at a 8% simple interest?
(2) Richard took a loan of $5200 at the rate of 8% simple interest per annum. If he paid an amount of $8528 to clear the loan, then find the time period of the loan.
(3) What amount will be due after 2 years if Donald borrowed a sum of $3750 at a 6% simple interest?
(4) Find the amount to be paid if Barbara borrowed a sum of $5550 at 5% simple interest for 8 years.
(5) Calculate the amount due if Sarah borrowed a sum of $3850 at 6% simple interest for 4 years.
(6) Calculate the amount due if Michael borrowed a sum of $3300 at 10% simple interest for 4 years.
(7) Mary took a loan of $4100 at the rate of 8% simple interest per annum. If he paid an amount of $7380 to clear the loan, then find the time period of the loan.
(8) Calculate the amount due after 10 years if Elizabeth borrowed a sum of $5450 at a rate of 4% simple interest.
(9) Find the amount to be paid if Sarah borrowed a sum of $5850 at 3% simple interest for 7 years.
(10) What amount does Thomas have to pay after 6 years if he takes a loan of $3800 at 5% simple interest?