Question:
Calculate the amount due if James borrowed a sum of $3000 at 7% simple interest for 3 years.
Correct Answer
$3630
Solution And Explanation
Solution
Given,
Principal (P) = $3000
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) = $3000 × 7% × 3
= $3000 ×7/100 × 3
= 3000 × 7 × 3/100
= 21000 × 3/100
= 63000/100
= $630
Thus, Simple Interest = $630
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 = $3000 + $630
= $3630
Thus, Amount to be paid = $3630 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 = $3000
Rate of Simple Interest (SI) or (R) = 7%
And, Time (t) = 3 years
Thus, Amount (A)
= $3000 + ($3000 × 7% × 3)
= $3000 + ($3000 ×7/100 × 3)
= $3000 + (3000 × 7 × 3/100)
= $3000 + (21000 × 3/100)
= $3000 + (63000/100)
= $3000 + $630 = $3630
Thus, Amount (A) to be paid = $3630 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 $3000, the simple interest in 1 year
= 7/100 × 3000
= 7 × 3000/100
= 21000/100 = $210
Thus, simple interest for 1 year = $210
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $210 × 3 = $630
Thus, Simple Interest (SI) = $630
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3000 + $630
= $3630
Thus, Amount to be paid = $3630 Answer
Similar Questions
(1) Find the amount to be paid if Patricia borrowed a sum of $5150 at 2% simple interest for 8 years.
(2) Calculate the amount due if Jennifer borrowed a sum of $3250 at 4% simple interest for 3 years.
(3) Calculate the amount due if Elizabeth borrowed a sum of $3450 at 9% simple interest for 3 years.
(4) Calculate the amount due if Christopher borrowed a sum of $4000 at 3% simple interest for 3 years.
(5) Lisa took a loan of $6100 at the rate of 8% simple interest per annum. If he paid an amount of $10004 to clear the loan, then find the time period of the loan.
(6) Calculate the amount due after 10 years if Jessica borrowed a sum of $5750 at a rate of 5% simple interest.
(7) Find the amount to be paid if Susan borrowed a sum of $5650 at 10% simple interest for 8 years.
(8) Sandra took a loan of $6900 at the rate of 9% simple interest per annum. If he paid an amount of $13110 to clear the loan, then find the time period of the loan.
(9) Calculate the amount due after 9 years if Susan borrowed a sum of $5650 at a rate of 3% simple interest.
(10) If Barbara borrowed $3550 from a bank at a rate of 2% simple interest per annum then find the amount to be paid after 2 years.