Simple Interest
MCQs Math


Question:     Calculate the amount due after 9 years if Elizabeth borrowed a sum of $5450 at a rate of 6% simple interest.


Correct Answer  $8393

Solution And Explanation

Solution

Given,

Principal (P) = $5450

Rate of Simple Interest (SI) = 6%

Time (t) = 9 years

Thus, Amount (A) = ?

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

Thus, here 6% simple interest means, Rate of Simple Interest (SI) is 6% 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) = $5450 × 6% × 9

= $5450 ×6/100 × 9

= 5450 × 6 × 9/100

= 32700 × 9/100

= 294300/100

= $2943

Thus, Simple Interest = $2943

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 = $5450 + $2943

= $8393

Thus, Amount to be paid = $8393 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 = $5450

Rate of Simple Interest (SI) or (R) = 6%

And, Time (t) = 9 years

Thus, Amount (A)

= $5450 + ($5450 × 6% × 9)

= $5450 + ($5450 ×6/100 × 9)

= $5450 + (5450 × 6 × 9/100)

= $5450 + (32700 × 9/100)

= $5450 + (294300/100)

= $5450 + $2943 = $8393

Thus, Amount (A) to be paid = $8393 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 6%

This, means, $6 per $100 per year

∵ For $100, the simple interest for 1 year = $6

∴ For $1, the simple interest for 1 year = 6/100

∴ For $5450, the simple interest in 1 year

= 6/100 × 5450

= 6 × 5450/100

= 32700/100 = $327

Thus, simple interest for 1 year = $327

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $327 × 9 = $2943

Thus, Simple Interest (SI) = $2943

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5450 + $2943

= $8393

Thus, Amount to be paid = $8393 Answer


Similar Questions

(1) What amount does Patricia have to pay after 6 years if he takes a loan of $3150 at 10% simple interest?

(2) If William paid $3920 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(3) Sandra took a loan of $6900 at the rate of 7% simple interest per annum. If he paid an amount of $10764 to clear the loan, then find the time period of the loan.

(4) Jessica took a loan of $5500 at the rate of 7% simple interest per annum. If he paid an amount of $8580 to clear the loan, then find the time period of the loan.

(5) Betty took a loan of $6500 at the rate of 7% simple interest per annum. If he paid an amount of $9685 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due if Mary borrowed a sum of $3050 at 8% simple interest for 3 years.

(7) Calculate the amount due after 9 years if David borrowed a sum of $5400 at a rate of 10% simple interest.

(8) What amount does Linda have to pay after 5 years if he takes a loan of $3350 at 8% simple interest?

(9) Betty had to pay $4632.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 3% then find the sum borrowed.

(10) Calculate the amount due if Mary borrowed a sum of $3050 at 10% simple interest for 3 years.


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