Simple Interest
MCQs Math


Question:     Calculate the amount due if Jennifer borrowed a sum of $3250 at 10% simple interest for 4 years.


Correct Answer  $4550

Solution And Explanation

Solution

Given,

Principal (P) = $3250

Rate of Simple Interest (SI) = 10%

Time (t) = 4 years

Thus, Amount (A) = ?

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

Thus, here 10% simple interest means, Rate of Simple Interest (SI) is 10% 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) = $3250 × 10% × 4

= $3250 ×10/100 × 4

= 3250 × 10 × 4/100

= 32500 × 4/100

= 130000/100

= $1300

Thus, Simple Interest = $1300

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 = $3250 + $1300

= $4550

Thus, Amount to be paid = $4550 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 = $3250

Rate of Simple Interest (SI) or (R) = 10%

And, Time (t) = 4 years

Thus, Amount (A)

= $3250 + ($3250 × 10% × 4)

= $3250 + ($3250 ×10/100 × 4)

= $3250 + (3250 × 10 × 4/100)

= $3250 + (32500 × 4/100)

= $3250 + (130000/100)

= $3250 + $1300 = $4550

Thus, Amount (A) to be paid = $4550 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 10%

This, means, $10 per $100 per year

∵ For $100, the simple interest for 1 year = $10

∴ For $1, the simple interest for 1 year = 10/100

∴ For $3250, the simple interest in 1 year

= 10/100 × 3250

= 10 × 3250/100

= 32500/100 = $325

Thus, simple interest for 1 year = $325

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $325 × 4 = $1300

Thus, Simple Interest (SI) = $1300

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3250 + $1300

= $4550

Thus, Amount to be paid = $4550 Answer


Similar Questions

(1) How much loan did Betty borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $7500 to clear it?

(2) David took a loan of $4800 at the rate of 7% simple interest per annum. If he paid an amount of $6816 to clear the loan, then find the time period of the loan.

(3) How much loan did Emily borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $8437.5 to clear it?

(4) Nancy took a loan of $6300 at the rate of 9% simple interest per annum. If he paid an amount of $10269 to clear the loan, then find the time period of the loan.

(5) Lisa took a loan of $6100 at the rate of 9% simple interest per annum. If he paid an amount of $11590 to clear the loan, then find the time period of the loan.

(6) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 3% simple interest for 8 years.

(7) Betty took a loan of $6500 at the rate of 10% simple interest per annum. If he paid an amount of $10400 to clear the loan, then find the time period of the loan.

(8) In how much time a principal of $3050 will amount to $3233 at a simple interest of 2% per annum?

(9) Calculate the amount due after 9 years if Thomas borrowed a sum of $5800 at a rate of 9% simple interest.

(10) How much loan did Jacob borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $8800 to clear it?


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