Question:
Calculate the amount due after 10 years if Robert borrowed a sum of $5100 at a rate of 3% simple interest.
Correct Answer
$6630
Solution And Explanation
Solution
Given,
Principal (P) = $5100
Rate of Simple Interest (SI) = 3%
Time (t) = 10 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) = $5100 × 3% × 10
= $5100 ×3/100 × 10
= 5100 × 3 × 10/100
= 15300 × 10/100
= 153000/100
= $1530
Thus, Simple Interest = $1530
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 = $5100 + $1530
= $6630
Thus, Amount to be paid = $6630 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 = $5100
Rate of Simple Interest (SI) or (R) = 3%
And, Time (t) = 10 years
Thus, Amount (A)
= $5100 + ($5100 × 3% × 10)
= $5100 + ($5100 ×3/100 × 10)
= $5100 + (5100 × 3 × 10/100)
= $5100 + (15300 × 10/100)
= $5100 + (153000/100)
= $5100 + $1530 = $6630
Thus, Amount (A) to be paid = $6630 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 $5100, the simple interest in 1 year
= 3/100 × 5100
= 3 × 5100/100
= 15300/100 = $153
Thus, simple interest for 1 year = $153
Therefore, simple interest for 10 years
= Simple interest for 1 year × 10
= $153 × 10 = $1530
Thus, Simple Interest (SI) = $1530
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $5100 + $1530
= $6630
Thus, Amount to be paid = $6630 Answer
Similar Questions
(1) Find the amount to be paid if Richard borrowed a sum of $5600 at 9% simple interest for 8 years.
(2) Find the amount to be paid if Sarah borrowed a sum of $5850 at 4% simple interest for 8 years.
(3) Find the amount to be paid if Patricia borrowed a sum of $5150 at 2% simple interest for 7 years.
(4) Find the amount to be paid if Robert borrowed a sum of $5100 at 3% simple interest for 8 years.
(5) Calculate the amount due if Thomas borrowed a sum of $3800 at 9% simple interest for 4 years.
(6) What amount does Christopher have to pay after 5 years if he takes a loan of $4000 at 7% simple interest?
(7) If Paul paid $5452 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.
(8) Calculate the amount due if Christopher borrowed a sum of $4000 at 6% simple interest for 3 years.
(9) Steven had to pay $5290 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.
(10) How much loan did Mary borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $6312.5 to clear it?