Simple Interest
MCQs Math


Question:     Calculate the amount due if Sarah borrowed a sum of $3850 at 9% simple interest for 3 years.


Correct Answer  $4889.5

Solution And Explanation

Solution

Given,

Principal (P) = $3850

Rate of Simple Interest (SI) = 9%

Time (t) = 3 years

Thus, Amount (A) = ?

The Rate of Interest is always calculated per annum, i.e. per year.

Thus, here 9% simple interest means, Rate of Simple Interest (SI) is 9% 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 × 9% × 3

= $3850 ×9/100 × 3

= 3850 × 9 × 3/100

= 34650 × 3/100

= 103950/100

= $1039.5

Thus, Simple Interest = $1039.5

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 + $1039.5

= $4889.5

Thus, Amount to be paid = $4889.5 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) = 9%

And, Time (t) = 3 years

Thus, Amount (A)

= $3850 + ($3850 × 9% × 3)

= $3850 + ($3850 ×9/100 × 3)

= $3850 + (3850 × 9 × 3/100)

= $3850 + (34650 × 3/100)

= $3850 + (103950/100)

= $3850 + $1039.5 = $4889.5

Thus, Amount (A) to be paid = $4889.5 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 9%

This, means, $9 per $100 per year

∵ For $100, the simple interest for 1 year = $9

∴ For $1, the simple interest for 1 year = 9/100

∴ For $3850, the simple interest in 1 year

= 9/100 × 3850

= 9 × 3850/100

= 34650/100 = $346.5

Thus, simple interest for 1 year = $346.5

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $346.5 × 3 = $1039.5

Thus, Simple Interest (SI) = $1039.5

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3850 + $1039.5

= $4889.5

Thus, Amount to be paid = $4889.5 Answer


Similar Questions

(1) Calculate the amount due after 10 years if Robert borrowed a sum of $5100 at a rate of 3% simple interest.

(2) Calculate the amount due if Richard borrowed a sum of $3600 at 6% simple interest for 3 years.

(3) Christopher took a loan of $6000 at the rate of 7% simple interest per annum. If he paid an amount of $8520 to clear the loan, then find the time period of the loan.

(4) James took a loan of $4000 at the rate of 7% simple interest per annum. If he paid an amount of $5960 to clear the loan, then find the time period of the loan.

(5) James took a loan of $4000 at the rate of 6% simple interest per annum. If he paid an amount of $5920 to clear the loan, then find the time period of the loan.

(6) What amount does Elizabeth have to pay after 6 years if he takes a loan of $3450 at 5% simple interest?

(7) If Mary paid $3538 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(8) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 3% simple interest for 7 years.

(9) Christopher took a loan of $6000 at the rate of 7% simple interest per annum. If he paid an amount of $10200 to clear the loan, then find the time period of the loan.

(10) Calculate the amount due if Michael borrowed a sum of $3300 at 6% simple interest for 4 years.


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