Question:
Calculate the amount due if Susan borrowed a sum of $3650 at 7% simple interest for 4 years.
Correct Answer
$4672
Solution And Explanation
Solution
Given,
Principal (P) = $3650
Rate of Simple Interest (SI) = 7%
Time (t) = 4 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) = $3650 × 7% × 4
= $3650 ×7/100 × 4
= 3650 × 7 × 4/100
= 25550 × 4/100
= 102200/100
= $1022
Thus, Simple Interest = $1022
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 = $3650 + $1022
= $4672
Thus, Amount to be paid = $4672 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 = $3650
Rate of Simple Interest (SI) or (R) = 7%
And, Time (t) = 4 years
Thus, Amount (A)
= $3650 + ($3650 × 7% × 4)
= $3650 + ($3650 ×7/100 × 4)
= $3650 + (3650 × 7 × 4/100)
= $3650 + (25550 × 4/100)
= $3650 + (102200/100)
= $3650 + $1022 = $4672
Thus, Amount (A) to be paid = $4672 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 $3650, the simple interest in 1 year
= 7/100 × 3650
= 7 × 3650/100
= 25550/100 = $255.5
Thus, simple interest for 1 year = $255.5
Therefore, simple interest for 4 years
= Simple interest for 1 year × 4
= $255.5 × 4 = $1022
Thus, Simple Interest (SI) = $1022
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3650 + $1022
= $4672
Thus, Amount to be paid = $4672 Answer
Similar Questions
(1) In how much time a principal of $3100 will amount to $3565 at a simple interest of 3% per annum?
(2) What amount will be due after 2 years if John borrowed a sum of $3100 at a 10% simple interest?
(3) What amount will be due after 2 years if Richard borrowed a sum of $3300 at a 5% simple interest?
(4) Calculate the amount due after 10 years if Susan borrowed a sum of $5650 at a rate of 3% simple interest.
(5) In how much time a principal of $3100 will amount to $3286 at a simple interest of 3% per annum?
(6) If Michael paid $3960 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.
(7) Jessica took a loan of $5500 at the rate of 7% simple interest per annum. If he paid an amount of $8965 to clear the loan, then find the time period of the loan.
(8) Calculate the amount due if David borrowed a sum of $3400 at 5% simple interest for 4 years.
(9) Find the amount to be paid if Christopher borrowed a sum of $6000 at 5% simple interest for 7 years.
(10) Calculate the amount due if Linda borrowed a sum of $3350 at 10% simple interest for 3 years.