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 if David borrowed a sum of $3400 at 4% simple interest for 4 years.

(2) Susan took a loan of $5300 at the rate of 8% simple interest per annum. If he paid an amount of $9540 to clear the loan, then find the time period of the loan.

(3) James took a loan of $4000 at the rate of 8% simple interest per annum. If he paid an amount of $6880 to clear the loan, then find the time period of the loan.

(4) What amount does Jennifer have to pay after 5 years if he takes a loan of $3250 at 9% simple interest?

(5) What amount does James have to pay after 6 years if he takes a loan of $3000 at 5% simple interest?

(6) Anthony took a loan of $6600 at the rate of 6% simple interest per annum. If he paid an amount of $10164 to clear the loan, then find the time period of the loan.

(7) What amount does Charles have to pay after 5 years if he takes a loan of $3900 at 8% simple interest?

(8) What amount does Thomas have to pay after 5 years if he takes a loan of $3800 at 8% simple interest?

(9) Matthew took a loan of $6400 at the rate of 8% simple interest per annum. If he paid an amount of $10496 to clear the loan, then find the time period of the loan.

(10) What amount does Joseph have to pay after 5 years if he takes a loan of $3700 at 9% simple interest?


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