Question:
Calculate the amount due if Michael borrowed a sum of $3300 at 7% simple interest for 3 years.
Correct Answer
$3993
Solution And Explanation
Solution
Given,
Principal (P) = $3300
Rate of Simple Interest (SI) = 7%
Time (t) = 3 years
Thus, Amount (A) = ?
The Rate of Interest is always calculated per annum, i.e. per year.
Thus, here 7% simple interest means, Rate of Simple Interest (SI) is 7% 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) = $3300 × 7% × 3
= $3300 ×7/100 × 3
= 3300 × 7 × 3/100
= 23100 × 3/100
= 69300/100
= $693
Thus, Simple Interest = $693
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 = $3300 + $693
= $3993
Thus, Amount to be paid = $3993 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 = $3300
Rate of Simple Interest (SI) or (R) = 7%
And, Time (t) = 3 years
Thus, Amount (A)
= $3300 + ($3300 × 7% × 3)
= $3300 + ($3300 ×7/100 × 3)
= $3300 + (3300 × 7 × 3/100)
= $3300 + (23100 × 3/100)
= $3300 + (69300/100)
= $3300 + $693 = $3993
Thus, Amount (A) to be paid = $3993 Answer
Method (3) Unitary Method
Calculation of Amount using Unitary Method
Calculation of Interest using Unitary Method
Here, given Rate of Simple Interest = 7%
This, means, $7 per $100 per year
∵ For $100, the simple interest for 1 year = $7
∴ For $1, the simple interest for 1 year = 7/100
∴ For $3300, the simple interest in 1 year
= 7/100 × 3300
= 7 × 3300/100
= 23100/100 = $231
Thus, simple interest for 1 year = $231
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $231 × 3 = $693
Thus, Simple Interest (SI) = $693
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3300 + $693
= $3993
Thus, Amount to be paid = $3993 Answer
Similar Questions
(1) Calculate the amount due after 9 years if Robert borrowed a sum of $5100 at a rate of 8% simple interest.
(2) What amount does Patricia have to pay after 6 years if he takes a loan of $3150 at 6% simple interest?
(3) How much loan did Emily borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $8437.5 to clear it?
(4) Calculate the amount due if Joseph borrowed a sum of $3700 at 4% simple interest for 3 years.
(5) What amount does Mary have to pay after 5 years if he takes a loan of $3050 at 9% simple interest?
(6) If Joseph paid $4292 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.
(7) Patricia took a loan of $4300 at the rate of 6% simple interest per annum. If he paid an amount of $6622 to clear the loan, then find the time period of the loan.
(8) What amount does Christopher have to pay after 5 years if he takes a loan of $4000 at 7% simple interest?
(9) Calculate the amount due if Susan borrowed a sum of $3650 at 8% simple interest for 3 years.
(10) Calculate the amount due after 10 years if Robert borrowed a sum of $5100 at a rate of 2% simple interest.