Simple Interest
MCQs Math


Question:     Calculate the amount due after 9 years if Robert borrowed a sum of $5100 at a rate of 2% simple interest.


Correct Answer  $6018

Solution And Explanation

Solution

Given,

Principal (P) = $5100

Rate of Simple Interest (SI) = 2%

Time (t) = 9 years

Thus, Amount (A) = ?

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

Thus, here 2% simple interest means, Rate of Simple Interest (SI) is 2% 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) = $5100 × 2% × 9

= $5100 ×2/100 × 9

= 5100 × 2 × 9/100

= 10200 × 9/100

= 91800/100

= $918

Thus, Simple Interest = $918

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 = $5100 + $918

= $6018

Thus, Amount to be paid = $6018 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 = $5100

Rate of Simple Interest (SI) or (R) = 2%

And, Time (t) = 9 years

Thus, Amount (A)

= $5100 + ($5100 × 2% × 9)

= $5100 + ($5100 ×2/100 × 9)

= $5100 + (5100 × 2 × 9/100)

= $5100 + (10200 × 9/100)

= $5100 + (91800/100)

= $5100 + $918 = $6018

Thus, Amount (A) to be paid = $6018 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 2%

This, means, $2 per $100 per year

∵ For $100, the simple interest for 1 year = $2

∴ For $1, the simple interest for 1 year = 2/100

∴ For $5100, the simple interest in 1 year

= 2/100 × 5100

= 2 × 5100/100

= 10200/100 = $102

Thus, simple interest for 1 year = $102

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $102 × 9 = $918

Thus, Simple Interest (SI) = $918

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5100 + $918

= $6018

Thus, Amount to be paid = $6018 Answer


Similar Questions

(1) How much loan did John borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $5720 to clear it?

(2) Patricia took a loan of $4300 at the rate of 6% simple interest per annum. If he paid an amount of $6106 to clear the loan, then find the time period of the loan.

(3) Calculate the amount due after 10 years if James borrowed a sum of $5000 at a rate of 9% simple interest.

(4) How much loan did Christopher borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $7500 to clear it?

(5) Calculate the amount due if Michael borrowed a sum of $3300 at 3% simple interest for 4 years.

(6) Mark had to pay $5060 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(7) Find the amount to be paid if William borrowed a sum of $5500 at 4% simple interest for 7 years.

(8) Joseph took a loan of $5400 at the rate of 9% simple interest per annum. If he paid an amount of $9774 to clear the loan, then find the time period of the loan.

(9) Margaret took a loan of $6700 at the rate of 10% simple interest per annum. If he paid an amount of $10720 to clear the loan, then find the time period of the loan.

(10) Calculate the amount due if Richard borrowed a sum of $3600 at 8% simple interest for 4 years.


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