Simple Interest
MCQs Math


Question:     Calculate the amount due after 10 years if Mary borrowed a sum of $5050 at a rate of 3% simple interest.


Correct Answer  $6565

Solution And Explanation

Solution

Given,

Principal (P) = $5050

Rate of Simple Interest (SI) = 3%

Time (t) = 10 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) = $5050 × 3% × 10

= $5050 ×3/100 × 10

= 5050 × 3 × 10/100

= 15150 × 10/100

= 151500/100

= $1515

Thus, Simple Interest = $1515

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 = $5050 + $1515

= $6565

Thus, Amount to be paid = $6565 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 = $5050

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

And, Time (t) = 10 years

Thus, Amount (A)

= $5050 + ($5050 × 3% × 10)

= $5050 + ($5050 ×3/100 × 10)

= $5050 + (5050 × 3 × 10/100)

= $5050 + (15150 × 10/100)

= $5050 + (151500/100)

= $5050 + $1515 = $6565

Thus, Amount (A) to be paid = $6565 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 $5050, the simple interest in 1 year

= 3/100 × 5050

= 3 × 5050/100

= 15150/100 = $151.5

Thus, simple interest for 1 year = $151.5

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $151.5 × 10 = $1515

Thus, Simple Interest (SI) = $1515

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5050 + $1515

= $6565

Thus, Amount to be paid = $6565 Answer


Similar Questions

(1) Calculate the amount due after 10 years if Susan borrowed a sum of $5650 at a rate of 5% simple interest.

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

(3) Calculate the amount due if Joseph borrowed a sum of $3700 at 4% simple interest for 4 years.

(4) Sandra took a loan of $6900 at the rate of 7% simple interest per annum. If he paid an amount of $11730 to clear the loan, then find the time period of the loan.

(5) Lisa took a loan of $6100 at the rate of 6% simple interest per annum. If he paid an amount of $9760 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due after 10 years if David borrowed a sum of $5400 at a rate of 8% simple interest.

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

(8) Linda had to pay $3752 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(9) Calculate the amount due if Barbara borrowed a sum of $3550 at 5% simple interest for 4 years.

(10) What amount will be due after 2 years if David borrowed a sum of $3200 at a 10% simple interest?


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