Question:
Calculate the amount due if John borrowed a sum of $3200 at 10% simple interest for 3 years.
Correct Answer
$4160
Solution And Explanation
Solution
Given,
Principal (P) = $3200
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) = $3200 × 10% × 3
= $3200 ×10/100 × 3
= 3200 × 10 × 3/100
= 32000 × 3/100
= 96000/100
= $960
Thus, Simple Interest = $960
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 = $3200 + $960
= $4160
Thus, Amount to be paid = $4160 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 = $3200
Rate of Simple Interest (SI) or (R) = 10%
And, Time (t) = 3 years
Thus, Amount (A)
= $3200 + ($3200 × 10% × 3)
= $3200 + ($3200 ×10/100 × 3)
= $3200 + (3200 × 10 × 3/100)
= $3200 + (32000 × 3/100)
= $3200 + (96000/100)
= $3200 + $960 = $4160
Thus, Amount (A) to be paid = $4160 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 $3200, the simple interest in 1 year
= 10/100 × 3200
= 10 × 3200/100
= 32000/100 = $320
Thus, simple interest for 1 year = $320
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $320 × 3 = $960
Thus, Simple Interest (SI) = $960
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3200 + $960
= $4160
Thus, Amount to be paid = $4160 Answer
Similar Questions
(1) If Sandra paid $4806 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.
(2) Calculate the amount due if Susan borrowed a sum of $3650 at 3% simple interest for 3 years.
(3) Christopher took a loan of $6000 at the rate of 8% simple interest per annum. If he paid an amount of $9360 to clear the loan, then find the time period of the loan.
(4) What amount will be due after 2 years if James borrowed a sum of $3000 at a 7% simple interest?
(5) What amount does James have to pay after 6 years if he takes a loan of $3000 at 2% simple interest?
(6) Jennifer took a loan of $4500 at the rate of 8% simple interest per annum. If he paid an amount of $7740 to clear the loan, then find the time period of the loan.
(7) What amount will be due after 2 years if Donald borrowed a sum of $3750 at a 9% simple interest?
(8) How much loan did Elizabeth borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $6812.5 to clear it?
(9) How much loan did Rebecca borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $8415 to clear it?
(10) Jessica took a loan of $5500 at the rate of 7% simple interest per annum. If he paid an amount of $8965 to clear the loan, then find the time period of the loan.