Question:
Calculate the amount due if Sarah borrowed a sum of $3850 at 4% simple interest for 3 years.
Correct Answer
$4312
Solution And Explanation
Solution
Given,
Principal (P) = $3850
Rate of Simple Interest (SI) = 4%
Time (t) = 3 years
Thus, Amount (A) = ?
The Rate of Interest is always calculated per annum, i.e. per year.
Thus, here 4% simple interest means, Rate of Simple Interest (SI) is 4% 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) = $3850 × 4% × 3
= $3850 ×4/100 × 3
= 3850 × 4 × 3/100
= 15400 × 3/100
= 46200/100
= $462
Thus, Simple Interest = $462
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 = $3850 + $462
= $4312
Thus, Amount to be paid = $4312 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 = $3850
Rate of Simple Interest (SI) or (R) = 4%
And, Time (t) = 3 years
Thus, Amount (A)
= $3850 + ($3850 × 4% × 3)
= $3850 + ($3850 ×4/100 × 3)
= $3850 + (3850 × 4 × 3/100)
= $3850 + (15400 × 3/100)
= $3850 + (46200/100)
= $3850 + $462 = $4312
Thus, Amount (A) to be paid = $4312 Answer
Method (3) Unitary Method
Calculation of Amount using Unitary Method
Calculation of Interest using Unitary Method
Here, given Rate of Simple Interest = 4%
This, means, $4 per $100 per year
∵ For $100, the simple interest for 1 year = $4
∴ For $1, the simple interest for 1 year = 4/100
∴ For $3850, the simple interest in 1 year
= 4/100 × 3850
= 4 × 3850/100
= 15400/100 = $154
Thus, simple interest for 1 year = $154
Therefore, simple interest for 3 years
= Simple interest for 1 year × 3
= $154 × 3 = $462
Thus, Simple Interest (SI) = $462
Calculation of Amount
Amount = Principal + Interest
Thus, Amount = $3850 + $462
= $4312
Thus, Amount to be paid = $4312 Answer
Similar Questions
(1) Sandra took a loan of $6900 at the rate of 8% simple interest per annum. If he paid an amount of $12420 to clear the loan, then find the time period of the loan.
(2) What amount does Karen have to pay after 5 years if he takes a loan of $3950 at 5% simple interest?
(3) Emily had to pay $5462.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.
(4) Lisa took a loan of $6100 at the rate of 10% simple interest per annum. If he paid an amount of $10370 to clear the loan, then find the time period of the loan.
(5) Find the amount to be paid if Mary borrowed a sum of $5050 at 9% simple interest for 8 years.
(6) Calculate the amount due after 9 years if Barbara borrowed a sum of $5550 at a rate of 4% simple interest.
(7) What amount does Patricia have to pay after 6 years if he takes a loan of $3150 at 10% simple interest?
(8) Calculate the amount due after 9 years if Christopher borrowed a sum of $6000 at a rate of 10% simple interest.
(9) Sandra took a loan of $6900 at the rate of 7% simple interest per annum. If he paid an amount of $10281 to clear the loan, then find the time period of the loan.
(10) Calculate the amount due if Thomas borrowed a sum of $3800 at 5% simple interest for 3 years.