Simple Interest
MCQs Math


Question:     Find the amount to be paid if William borrowed a sum of $5500 at 3% simple interest for 8 years.


Correct Answer  $6820

Solution And Explanation

Solution

Given,

Principal (P) = $5500

Rate of Simple Interest (SI) = 3%

Time (t) = 8 years

Thus, Amount (A) = ?

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

Thus, here 3% simple interest means, Rate of Simple Interest (SI) is 3% 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) = $5500 × 3% × 8

= $5500 ×3/100 × 8

= 5500 × 3 × 8/100

= 16500 × 8/100

= 132000/100

= $1320

Thus, Simple Interest = $1320

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 = $5500 + $1320

= $6820

Thus, Amount to be paid = $6820 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 = $5500

Rate of Simple Interest (SI) or (R) = 3%

And, Time (t) = 8 years

Thus, Amount (A)

= $5500 + ($5500 × 3% × 8)

= $5500 + ($5500 ×3/100 × 8)

= $5500 + (5500 × 3 × 8/100)

= $5500 + (16500 × 8/100)

= $5500 + (132000/100)

= $5500 + $1320 = $6820

Thus, Amount (A) to be paid = $6820 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 3%

This, means, $3 per $100 per year

∵ For $100, the simple interest for 1 year = $3

∴ For $1, the simple interest for 1 year = 3/100

∴ For $5500, the simple interest in 1 year

= 3/100 × 5500

= 3 × 5500/100

= 16500/100 = $165

Thus, simple interest for 1 year = $165

Therefore, simple interest for 8 years

= Simple interest for 1 year × 8

= $165 × 8 = $1320

Thus, Simple Interest (SI) = $1320

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5500 + $1320

= $6820

Thus, Amount to be paid = $6820 Answer


Similar Questions

(1) Lisa took a loan of $6100 at the rate of 7% simple interest per annum. If he paid an amount of $9089 to clear the loan, then find the time period of the loan.

(2) Calculate the amount due if William borrowed a sum of $3500 at 2% simple interest for 3 years.

(3) Daniel took a loan of $6200 at the rate of 8% simple interest per annum. If he paid an amount of $10664 to clear the loan, then find the time period of the loan.

(4) How much loan did William borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $6600 to clear it?

(5) Anthony took a loan of $6600 at the rate of 8% simple interest per annum. If he paid an amount of $9768 to clear the loan, then find the time period of the loan.

(6) Thomas took a loan of $5600 at the rate of 7% simple interest per annum. If he paid an amount of $7952 to clear the loan, then find the time period of the loan.

(7) Calculate the amount due if Joseph borrowed a sum of $3700 at 8% simple interest for 3 years.

(8) Calculate the amount due after 10 years if Richard borrowed a sum of $5600 at a rate of 3% simple interest.

(9) Calculate the amount due after 9 years if Susan borrowed a sum of $5650 at a rate of 7% simple interest.

(10) Mary took a loan of $4100 at the rate of 8% simple interest per annum. If he paid an amount of $7052 to clear the loan, then find the time period of the loan.


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