Simple Interest
MCQs Math


Question:     Find the amount to be paid if Christopher borrowed a sum of $6000 at 8% simple interest for 8 years.


Correct Answer  $9840

Solution And Explanation

Solution

Given,

Principal (P) = $6000

Rate of Simple Interest (SI) = 8%

Time (t) = 8 years

Thus, Amount (A) = ?

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

Thus, here 8% simple interest means, Rate of Simple Interest (SI) is 8% 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) = $6000 × 8% × 8

= $6000 ×8/100 × 8

= 6000 × 8 × 8/100

= 48000 × 8/100

= 384000/100

= $3840

Thus, Simple Interest = $3840

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 = $6000 + $3840

= $9840

Thus, Amount to be paid = $9840 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 = $6000

Rate of Simple Interest (SI) or (R) = 8%

And, Time (t) = 8 years

Thus, Amount (A)

= $6000 + ($6000 × 8% × 8)

= $6000 + ($6000 ×8/100 × 8)

= $6000 + (6000 × 8 × 8/100)

= $6000 + (48000 × 8/100)

= $6000 + (384000/100)

= $6000 + $3840 = $9840

Thus, Amount (A) to be paid = $9840 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 8%

This, means, $8 per $100 per year

∵ For $100, the simple interest for 1 year = $8

∴ For $1, the simple interest for 1 year = 8/100

∴ For $6000, the simple interest in 1 year

= 8/100 × 6000

= 8 × 6000/100

= 48000/100 = $480

Thus, simple interest for 1 year = $480

Therefore, simple interest for 8 years

= Simple interest for 1 year × 8

= $480 × 8 = $3840

Thus, Simple Interest (SI) = $3840

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $6000 + $3840

= $9840

Thus, Amount to be paid = $9840 Answer


Similar Questions

(1) Calculate the amount due after 10 years if Michael borrowed a sum of $5300 at a rate of 3% simple interest.

(2) Calculate the amount due after 9 years if Robert borrowed a sum of $5100 at a rate of 8% simple interest.

(3) Nancy took a loan of $6300 at the rate of 10% simple interest per annum. If he paid an amount of $10080 to clear the loan, then find the time period of the loan.

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

(5) Michael took a loan of $4600 at the rate of 7% simple interest per annum. If he paid an amount of $6854 to clear the loan, then find the time period of the loan.

(6) Karen took a loan of $5900 at the rate of 7% simple interest per annum. If he paid an amount of $8791 to clear the loan, then find the time period of the loan.

(7) Sarah took a loan of $5700 at the rate of 7% simple interest per annum. If he paid an amount of $8094 to clear the loan, then find the time period of the loan.

(8) Calculate the amount due if Thomas borrowed a sum of $3800 at 4% simple interest for 4 years.

(9) What amount will be due after 2 years if Christopher borrowed a sum of $3500 at a 7% simple interest?

(10) Donald took a loan of $7000 at the rate of 7% simple interest per annum. If he paid an amount of $10920 to clear the loan, then find the time period of the loan.


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