Question:
Calculate the amount due if James borrowed a sum of $3000 at 10% simple interest for 3 years.
Correct Answer
$3900
Solution And Explanation
Solution
Given,
Principal (P) = $3000
Rate of Simple Interest (SI) = 10%
Time (t) = 3 years
Thus, Amount (A) = ?
The Rate of Interest is always calculated per annum, i.e. per year.
Thus, here 10% simple interest means, Rate of Simple Interest (SI) is 10% 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) = $3000 × 10% × 3
= $3000 ×10/100 × 3
= 3000 × 10 × 3/100
= 30000 × 3/100
= 90000/100
= $900
Thus, Simple Interest = $900
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 = $3000 + $900
= $3900
Thus, Amount to be paid = $3900 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 = $3000
Rate of Simple Interest (SI) or (R) = 10%
And, Time (t) = 3 years
Thus, Amount (A)
= $3000 + ($3000 × 10% × 3)
= $3000 + ($3000 ×10/100 × 3)
= $3000 + (3000 × 10 × 3/100)
= $3000 + (30000 × 3/100)
= $3000 + (90000/100)
= $3000 + $900 = $3900
Thus, Amount (A) to be paid = $3900 Answer
Method (3) Unitary Method
Calculation of Amount using Unitary Method
Calculation of Interest using Unitary Method
Here, given Rate of Simple Interest = 10%
This, means, $10 per $100 per year
∵ For $100, the simple interest for 1 year = $10
∴ For $1, the simple interest for 1 year = 10/100
∴ For $3000, the simple interest in 1 year
= 10/100 × 3000
= 10 × 3000/100
= 30000/100 = $300
Thus, simple interest for 1 year = $300
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $300 × 3 = $900
Thus, Simple Interest (SI) = $900
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3000 + $900
= $3900
Thus, Amount to be paid = $3900 Answer
Similar Questions
(1) What amount does Jennifer have to pay after 6 years if he takes a loan of $3250 at 9% simple interest?
(2) In how much time a principal of $3100 will amount to $3348 at a simple interest of 2% per annum?
(3) Calculate the amount due if Michael borrowed a sum of $3300 at 6% simple interest for 3 years.
(4) How much loan did Sarah borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $7020 to clear it?
(5) What amount does John have to pay after 6 years if he takes a loan of $3200 at 9% simple interest?
(6) What amount will be due after 2 years if Paul borrowed a sum of $3850 at a 6% simple interest?
(7) Calculate the amount due if Barbara borrowed a sum of $3550 at 3% simple interest for 4 years.
(8) Matthew took a loan of $6400 at the rate of 6% simple interest per annum. If he paid an amount of $10240 to clear the loan, then find the time period of the loan.
(9) Thomas took a loan of $5600 at the rate of 10% simple interest per annum. If he paid an amount of $11200 to clear the loan, then find the time period of the loan.
(10) Barbara had to pay $3763 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.