Question:
Calculate the amount due if Robert borrowed a sum of $3100 at 3% simple interest for 4 years.
Correct Answer
$3472
Solution And Explanation
Solution
Given,
Principal (P) = $3100
Rate of Simple Interest (SI) = 3%
Time (t) = 4 years
Thus, Amount (A) = ?
The Rate of Interest is always calculated per annum, i.e. per year.
Thus, here 3% simple interest means, Rate of Simple Interest (SI) is 3% 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) = $3100 × 3% × 4
= $3100 ×3/100 × 4
= 3100 × 3 × 4/100
= 9300 × 4/100
= 37200/100
= $372
Thus, Simple Interest = $372
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 = $3100 + $372
= $3472
Thus, Amount to be paid = $3472 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 = $3100
Rate of Simple Interest (SI) or (R) = 3%
And, Time (t) = 4 years
Thus, Amount (A)
= $3100 + ($3100 × 3% × 4)
= $3100 + ($3100 ×3/100 × 4)
= $3100 + (3100 × 3 × 4/100)
= $3100 + (9300 × 4/100)
= $3100 + (37200/100)
= $3100 + $372 = $3472
Thus, Amount (A) to be paid = $3472 Answer
Method (3) Unitary Method
Calculation of Amount using Unitary Method
Calculation of Interest using Unitary Method
Here, given Rate of Simple Interest = 3%
This, means, $3 per $100 per year
∵ For $100, the simple interest for 1 year = $3
∴ For $1, the simple interest for 1 year = 3/100
∴ For $3100, the simple interest in 1 year
= 3/100 × 3100
= 3 × 3100/100
= 9300/100 = $93
Thus, simple interest for 1 year = $93
Therefore, simple interest for 4 years
= Simple interest for 1 year × 4
= $93 × 4 = $372
Thus, Simple Interest (SI) = $372
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3100 + $372
= $3472
Thus, Amount to be paid = $3472 Answer
Similar Questions
(1) What amount does David have to pay after 5 years if he takes a loan of $3400 at 3% simple interest?
(2) If Paul paid $5076 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.
(3) James took a loan of $4000 at the rate of 9% simple interest per annum. If he paid an amount of $7600 to clear the loan, then find the time period of the loan.
(4) What amount does Richard have to pay after 6 years if he takes a loan of $3600 at 6% simple interest?
(5) If Mark paid $4752 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.
(6) Calculate the amount due after 10 years if Mary borrowed a sum of $5050 at a rate of 4% simple interest.
(7) Calculate the amount due after 9 years if John borrowed a sum of $5200 at a rate of 7% simple interest.
(8) Jennifer had to pay $3640 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.
(9) Find the amount to be paid if Robert borrowed a sum of $5100 at 5% simple interest for 7 years.
(10) Anthony took a loan of $6600 at the rate of 8% simple interest per annum. If he paid an amount of $9768 to clear the loan, then find the time period of the loan.