Simple Interest
MCQs Math


Question:     Calculate the amount due if Thomas borrowed a sum of $3800 at 7% simple interest for 3 years.


Correct Answer  $4598

Solution And Explanation

Solution

Given,

Principal (P) = $3800

Rate of Simple Interest (SI) = 7%

Time (t) = 3 years

Thus, Amount (A) = ?

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

Thus, here 7% simple interest means, Rate of Simple Interest (SI) is 7% 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) = $3800 × 7% × 3

= $3800 ×7/100 × 3

= 3800 × 7 × 3/100

= 26600 × 3/100

= 79800/100

= $798

Thus, Simple Interest = $798

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 = $3800 + $798

= $4598

Thus, Amount to be paid = $4598 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 = $3800

Rate of Simple Interest (SI) or (R) = 7%

And, Time (t) = 3 years

Thus, Amount (A)

= $3800 + ($3800 × 7% × 3)

= $3800 + ($3800 ×7/100 × 3)

= $3800 + (3800 × 7 × 3/100)

= $3800 + (26600 × 3/100)

= $3800 + (79800/100)

= $3800 + $798 = $4598

Thus, Amount (A) to be paid = $4598 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 7%

This, means, $7 per $100 per year

∵ For $100, the simple interest for 1 year = $7

∴ For $1, the simple interest for 1 year = 7/100

∴ For $3800, the simple interest in 1 year

= 7/100 × 3800

= 7 × 3800/100

= 26600/100 = $266

Thus, simple interest for 1 year = $266

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $266 × 3 = $798

Thus, Simple Interest (SI) = $798

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3800 + $798

= $4598

Thus, Amount to be paid = $4598 Answer


Similar Questions

(1) Find the amount to be paid if Barbara borrowed a sum of $5550 at 8% simple interest for 8 years.

(2) Calculate the amount due after 9 years if Karen borrowed a sum of $5950 at a rate of 2% simple interest.

(3) Calculate the amount due after 9 years if Karen borrowed a sum of $5950 at a rate of 4% simple interest.

(4) Calculate the amount due if Karen borrowed a sum of $3950 at 2% simple interest for 3 years.

(5) How much loan did Michelle borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $7992.5 to clear it?

(6) How much loan did Ashley borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $7205 to clear it?

(7) How much loan did Sarah borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $6727.5 to clear it?

(8) Margaret took a loan of $6700 at the rate of 10% simple interest per annum. If he paid an amount of $11390 to clear the loan, then find the time period of the loan.

(9) Find the amount to be paid if Robert borrowed a sum of $5100 at 10% simple interest for 7 years.

(10) Calculate the amount due after 9 years if Jessica borrowed a sum of $5750 at a rate of 8% simple interest.


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