Question:
Calculate the amount due if Thomas borrowed a sum of $3800 at 10% simple interest for 3 years.
Correct Answer
$4940
Solution And Explanation
Solution
Given,
Principal (P) = $3800
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) = $3800 × 10% × 3
= $3800 ×10/100 × 3
= 3800 × 10 × 3/100
= 38000 × 3/100
= 114000/100
= $1140
Thus, Simple Interest = $1140
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 = $3800 + $1140
= $4940
Thus, Amount to be paid = $4940 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 = $3800
Rate of Simple Interest (SI) or (R) = 10%
And, Time (t) = 3 years
Thus, Amount (A)
= $3800 + ($3800 × 10% × 3)
= $3800 + ($3800 ×10/100 × 3)
= $3800 + (3800 × 10 × 3/100)
= $3800 + (38000 × 3/100)
= $3800 + (114000/100)
= $3800 + $1140 = $4940
Thus, Amount (A) to be paid = $4940 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 $3800, the simple interest in 1 year
= 10/100 × 3800
= 10 × 3800/100
= 38000/100 = $380
Thus, simple interest for 1 year = $380
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $380 × 3 = $1140
Thus, Simple Interest (SI) = $1140
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3800 + $1140
= $4940
Thus, Amount to be paid = $4940 Answer
Similar Questions
(1) If Joseph borrowed $3700 from a bank at a rate of 2% simple interest per annum then find the amount to be paid after 2 years.
(2) If Mary paid $3416 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.
(3) What amount will be due after 2 years if Charles borrowed a sum of $3450 at a 7% simple interest?
(4) Find the amount to be paid if Richard borrowed a sum of $5600 at 9% simple interest for 8 years.
(5) Anthony took a loan of $6600 at the rate of 9% simple interest per annum. If he paid an amount of $10164 to clear the loan, then find the time period of the loan.
(6) Mark took a loan of $6800 at the rate of 7% simple interest per annum. If he paid an amount of $10132 to clear the loan, then find the time period of the loan.
(7) Calculate the amount due after 9 years if Michael borrowed a sum of $5300 at a rate of 4% simple interest.
(8) Calculate the amount due if Sarah borrowed a sum of $3850 at 8% simple interest for 3 years.
(9) What amount does Jessica have to pay after 5 years if he takes a loan of $3750 at 5% simple interest?
(10) Charles took a loan of $5800 at the rate of 9% simple interest per annum. If he paid an amount of $10498 to clear the loan, then find the time period of the loan.