Simple Interest
MCQs Math


Question:     What amount does William have to pay after 5 years if he takes a loan of $3500 at 8% simple interest?


Correct Answer  $4900

Solution And Explanation

Solution

Given,

Principal (P) = $3500

Rate of Simple Interest (SI) = 8%

Time (t) = 5 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) = $3500 × 8% × 5

= $3500 ×8/100 × 5

= 3500 × 8 × 5/100

= 28000 × 5/100

= 140000/100

= $1400

Thus, Simple Interest = $1400

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 = $3500 + $1400

= $4900

Thus, Amount to be paid = $4900 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 = $3500

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

And, Time (t) = 5 years

Thus, Amount (A)

= $3500 + ($3500 × 8% × 5)

= $3500 + ($3500 ×8/100 × 5)

= $3500 + (3500 × 8 × 5/100)

= $3500 + (28000 × 5/100)

= $3500 + (140000/100)

= $3500 + $1400 = $4900

Thus, Amount (A) to be paid = $4900 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 $3500, the simple interest in 1 year

= 8/100 × 3500

= 8 × 3500/100

= 28000/100 = $280

Thus, simple interest for 1 year = $280

Therefore, simple interest for 5 years

= Simple interest for 1 year × 5

= $280 × 5 = $1400

Thus, Simple Interest (SI) = $1400

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3500 + $1400

= $4900

Thus, Amount to be paid = $4900 Answer


Similar Questions

(1) If Karen paid $4424 to settle his loan which he had taken 4 years before at a simple interest of 3%, 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) Linda took a loan of $4700 at the rate of 6% simple interest per annum. If he paid an amount of $6392 to clear the loan, then find the time period of the loan.

(4) Mark took a loan of $6800 at the rate of 9% simple interest per annum. If he paid an amount of $11084 to clear the loan, then find the time period of the loan.

(5) Calculate the amount due after 10 years if Joseph borrowed a sum of $5700 at a rate of 2% simple interest.

(6) Barbara took a loan of $5100 at the rate of 7% simple interest per annum. If he paid an amount of $8313 to clear the loan, then find the time period of the loan.

(7) If Kenneth paid $6000 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(8) Linda took a loan of $4700 at the rate of 10% simple interest per annum. If he paid an amount of $7990 to clear the loan, then find the time period of the loan.

(9) Barbara took a loan of $5100 at the rate of 8% simple interest per annum. If he paid an amount of $8364 to clear the loan, then find the time period of the loan.

(10) Find the amount to be paid if Sarah borrowed a sum of $5850 at 5% simple interest for 7 years.


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