Simple Interest
MCQs Math


Question:     Find the amount to be paid if James borrowed a sum of $5000 at 9% simple interest for 8 years.


Correct Answer  $8600

Solution And Explanation

Solution

Given,

Principal (P) = $5000

Rate of Simple Interest (SI) = 9%

Time (t) = 8 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) = $5000 × 9% × 8

= $5000 ×9/100 × 8

= 5000 × 9 × 8/100

= 45000 × 8/100

= 360000/100

= $3600

Thus, Simple Interest = $3600

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 = $5000 + $3600

= $8600

Thus, Amount to be paid = $8600 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 = $5000

Rate of Simple Interest (SI) or (R) = 9%

And, Time (t) = 8 years

Thus, Amount (A)

= $5000 + ($5000 × 9% × 8)

= $5000 + ($5000 ×9/100 × 8)

= $5000 + (5000 × 9 × 8/100)

= $5000 + (45000 × 8/100)

= $5000 + (360000/100)

= $5000 + $3600 = $8600

Thus, Amount (A) to be paid = $8600 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 $5000, the simple interest in 1 year

= 9/100 × 5000

= 9 × 5000/100

= 45000/100 = $450

Thus, simple interest for 1 year = $450

Therefore, simple interest for 8 years

= Simple interest for 1 year × 8

= $450 × 8 = $3600

Thus, Simple Interest (SI) = $3600

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5000 + $3600

= $8600

Thus, Amount to be paid = $8600 Answer


Similar Questions

(1) If Barbara paid $3834 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(2) Lisa took a loan of $6100 at the rate of 8% simple interest per annum. If he paid an amount of $9028 to clear the loan, then find the time period of the loan.

(3) Find the amount to be paid if James borrowed a sum of $5000 at 9% simple interest for 7 years.

(4) Mary took a loan of $4100 at the rate of 6% simple interest per annum. If he paid an amount of $5576 to clear the loan, then find the time period of the loan.

(5) Christopher took a loan of $6000 at the rate of 8% simple interest per annum. If he paid an amount of $9360 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due if William borrowed a sum of $3500 at 5% simple interest for 4 years.

(7) John took a loan of $4400 at the rate of 10% simple interest per annum. If he paid an amount of $8800 to clear the loan, then find the time period of the loan.

(8) Calculate the amount due after 9 years if Christopher borrowed a sum of $6000 at a rate of 9% simple interest.

(9) Find the amount to be paid if Mary borrowed a sum of $5050 at 5% simple interest for 7 years.

(10) In how much time a principal of $3050 will amount to $3294 at a simple interest of 4% per annum?


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