Question:
Calculate the amount due if Barbara borrowed a sum of $3550 at 10% simple interest for 3 years.
Correct Answer
$4615
Solution And Explanation
Solution
Given,
Principal (P) = $3550
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) = $3550 × 10% × 3
= $3550 ×10/100 × 3
= 3550 × 10 × 3/100
= 35500 × 3/100
= 106500/100
= $1065
Thus, Simple Interest = $1065
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 = $3550 + $1065
= $4615
Thus, Amount to be paid = $4615 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 = $3550
Rate of Simple Interest (SI) or (R) = 10%
And, Time (t) = 3 years
Thus, Amount (A)
= $3550 + ($3550 × 10% × 3)
= $3550 + ($3550 ×10/100 × 3)
= $3550 + (3550 × 10 × 3/100)
= $3550 + (35500 × 3/100)
= $3550 + (106500/100)
= $3550 + $1065 = $4615
Thus, Amount (A) to be paid = $4615 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 $3550, the simple interest in 1 year
= 10/100 × 3550
= 10 × 3550/100
= 35500/100 = $355
Thus, simple interest for 1 year = $355
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $355 × 3 = $1065
Thus, Simple Interest (SI) = $1065
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3550 + $1065
= $4615
Thus, Amount to be paid = $4615 Answer
Similar Questions
(1) Calculate the amount due after 10 years if Barbara borrowed a sum of $5550 at a rate of 6% simple interest.
(2) Robert took a loan of $4200 at the rate of 10% simple interest per annum. If he paid an amount of $7560 to clear the loan, then find the time period of the loan.
(3) Calculate the amount due if John borrowed a sum of $3200 at 4% simple interest for 3 years.
(4) Calculate the amount due after 9 years if Sarah borrowed a sum of $5850 at a rate of 3% simple interest.
(5) What amount does Thomas have to pay after 6 years if he takes a loan of $3800 at 4% simple interest?
(6) If Susan borrowed $3650 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 years.
(7) Calculate the amount due if Karen borrowed a sum of $3950 at 7% simple interest for 3 years.
(8) What amount does Linda have to pay after 6 years if he takes a loan of $3350 at 4% simple interest?
(9) In how much time a principal of $3200 will amount to $3392 at a simple interest of 3% per annum?
(10) Calculate the amount due after 10 years if Richard borrowed a sum of $5600 at a rate of 4% simple interest.