Simple Interest
MCQs Math


Question:     Calculate the amount due after 10 years if Barbara borrowed a sum of $5550 at a rate of 3% simple interest.


Correct Answer  $7215

Solution And Explanation

Solution

Given,

Principal (P) = $5550

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) = $5550 × 3% × 10

= $5550 ×3/100 × 10

= 5550 × 3 × 10/100

= 16650 × 10/100

= 166500/100

= $1665

Thus, Simple Interest = $1665

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 = $5550 + $1665

= $7215

Thus, Amount to be paid = $7215 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 = $5550

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

And, Time (t) = 10 years

Thus, Amount (A)

= $5550 + ($5550 × 3% × 10)

= $5550 + ($5550 ×3/100 × 10)

= $5550 + (5550 × 3 × 10/100)

= $5550 + (16650 × 10/100)

= $5550 + (166500/100)

= $5550 + $1665 = $7215

Thus, Amount (A) to be paid = $7215 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 $5550, the simple interest in 1 year

= 3/100 × 5550

= 3 × 5550/100

= 16650/100 = $166.5

Thus, simple interest for 1 year = $166.5

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $166.5 × 10 = $1665

Thus, Simple Interest (SI) = $1665

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5550 + $1665

= $7215

Thus, Amount to be paid = $7215 Answer


Similar Questions

(1) Find the amount to be paid if Sarah borrowed a sum of $5850 at 6% simple interest for 7 years.

(2) Find the amount to be paid if Michael borrowed a sum of $5300 at 2% simple interest for 8 years.

(3) Susan took a loan of $5300 at the rate of 6% simple interest per annum. If he paid an amount of $7844 to clear the loan, then find the time period of the loan.

(4) Nancy took a loan of $6300 at the rate of 9% simple interest per annum. If he paid an amount of $9702 to clear the loan, then find the time period of the loan.

(5) Calculate the amount due if Robert borrowed a sum of $3100 at 2% simple interest for 4 years.

(6) Find the amount to be paid if James borrowed a sum of $5000 at 5% simple interest for 8 years.

(7) John took a loan of $4400 at the rate of 7% simple interest per annum. If he paid an amount of $6248 to clear the loan, then find the time period of the loan.

(8) Calculate the amount due if Linda borrowed a sum of $3350 at 4% simple interest for 3 years.

(9) What amount does Susan have to pay after 6 years if he takes a loan of $3650 at 3% simple interest?

(10) Calculate the amount due if Christopher borrowed a sum of $4000 at 4% simple interest for 3 years.


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