Simple Interest
MCQs Math


Question:     What amount does Elizabeth have to pay after 6 years if he takes a loan of $3450 at 9% simple interest?


Correct Answer  $5313

Solution And Explanation

Solution

Given,

Principal (P) = $3450

Rate of Simple Interest (SI) = 9%

Time (t) = 6 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) = $3450 × 9% × 6

= $3450 ×9/100 × 6

= 3450 × 9 × 6/100

= 31050 × 6/100

= 186300/100

= $1863

Thus, Simple Interest = $1863

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 = $3450 + $1863

= $5313

Thus, Amount to be paid = $5313 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 = $3450

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

And, Time (t) = 6 years

Thus, Amount (A)

= $3450 + ($3450 × 9% × 6)

= $3450 + ($3450 ×9/100 × 6)

= $3450 + (3450 × 9 × 6/100)

= $3450 + (31050 × 6/100)

= $3450 + (186300/100)

= $3450 + $1863 = $5313

Thus, Amount (A) to be paid = $5313 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 $3450, the simple interest in 1 year

= 9/100 × 3450

= 9 × 3450/100

= 31050/100 = $310.5

Thus, simple interest for 1 year = $310.5

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $310.5 × 6 = $1863

Thus, Simple Interest (SI) = $1863

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3450 + $1863

= $5313

Thus, Amount to be paid = $5313 Answer


Similar Questions

(1) Calculate the amount due if William borrowed a sum of $3500 at 7% simple interest for 3 years.

(2) Find the amount to be paid if Robert borrowed a sum of $5100 at 9% simple interest for 7 years.

(3) Calculate the amount due if Karen borrowed a sum of $3950 at 2% simple interest for 3 years.

(4) Sarah took a loan of $5700 at the rate of 9% simple interest per annum. If he paid an amount of $8778 to clear the loan, then find the time period of the loan.

(5) Calculate the amount due after 10 years if Thomas borrowed a sum of $5800 at a rate of 8% simple interest.

(6) If Christopher borrowed $4000 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 years.

(7) Find the amount to be paid if David borrowed a sum of $5400 at 9% simple interest for 8 years.

(8) Mary took a loan of $4100 at the rate of 10% simple interest per annum. If he paid an amount of $6560 to clear the loan, then find the time period of the loan.

(9) Calculate the amount due after 10 years if Linda borrowed a sum of $5350 at a rate of 3% simple interest.

(10) What amount does Sarah have to pay after 6 years if he takes a loan of $3850 at 10% simple interest?


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