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) What amount will be due after 2 years if Robert borrowed a sum of $3050 at a 10% simple interest?
(2) What amount does Michael have to pay after 5 years if he takes a loan of $3300 at 10% simple interest?
(3) Calculate the amount due after 9 years if Sarah borrowed a sum of $5850 at a rate of 3% simple interest.
(4) Michael took a loan of $4600 at the rate of 10% simple interest per annum. If he paid an amount of $8740 to clear the loan, then find the time period of the loan.
(5) What amount will be due after 2 years if Steven borrowed a sum of $3800 at a 7% simple interest?
(6) If John paid $3712 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.
(7) What amount does Mary have to pay after 5 years if he takes a loan of $3050 at 10% simple interest?
(8) What amount does Charles have to pay after 5 years if he takes a loan of $3900 at 4% simple interest?
(9) If Margaret paid $5220 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.
(10) What amount will be due after 2 years if Daniel borrowed a sum of $3550 at a 10% simple interest?