Question:
Calculate the amount due if Charles borrowed a sum of $3900 at 6% simple interest for 3 years.
Correct Answer
$4602
Solution And Explanation
Solution
Given,
Principal (P) = $3900
Rate of Simple Interest (SI) = 6%
Time (t) = 3 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% × 3
= $3900 ×6/100 × 3
= 3900 × 6 × 3/100
= 23400 × 3/100
= 70200/100
= $702
Thus, Simple Interest = $702
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 + $702
= $4602
Thus, Amount to be paid = $4602 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) = 3 years
Thus, Amount (A)
= $3900 + ($3900 × 6% × 3)
= $3900 + ($3900 ×6/100 × 3)
= $3900 + (3900 × 6 × 3/100)
= $3900 + (23400 × 3/100)
= $3900 + (70200/100)
= $3900 + $702 = $4602
Thus, Amount (A) to be paid = $4602 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 3 years
= Simple interest for 1 year × 3
= $234 × 3 = $702
Thus, Simple Interest (SI) = $702
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3900 + $702
= $4602
Thus, Amount to be paid = $4602 Answer
Similar Questions
(1) Christopher took a loan of $6000 at the rate of 10% simple interest per annum. If he paid an amount of $12000 to clear the loan, then find the time period of the loan.
(2) Robert took a loan of $4200 at the rate of 9% simple interest per annum. If he paid an amount of $6846 to clear the loan, then find the time period of the loan.
(3) Calculate the amount due after 9 years if Christopher borrowed a sum of $6000 at a rate of 9% simple interest.
(4) Calculate the amount due if Barbara borrowed a sum of $3550 at 2% simple interest for 4 years.
(5) Sarah took a loan of $5700 at the rate of 8% simple interest per annum. If he paid an amount of $9804 to clear the loan, then find the time period of the loan.
(6) David took a loan of $4800 at the rate of 8% simple interest per annum. If he paid an amount of $7872 to clear the loan, then find the time period of the loan.
(7) Find the amount to be paid if Linda borrowed a sum of $5350 at 2% simple interest for 8 years.
(8) Calculate the amount due after 10 years if Sarah borrowed a sum of $5850 at a rate of 5% simple interest.
(9) In how much time a principal of $3050 will amount to $3294 at a simple interest of 4% per annum?
(10) What amount does Christopher have to pay after 5 years if he takes a loan of $4000 at 6% simple interest?