Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if Richard borrowed a sum of $5600 at a rate of 7% simple interest.

Correct Answer  $9128

Solution & Explanation

Solution

Given,

Principal (P) = $5600

Rate of Simple Interest (SI) = 7%

Time (t) = 9 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) = $5600 × 7% × 9

= $5600 ×⁷/₁₀₀ × 9

= ^{5600 × 7 × 9}/₁₀₀

= ^{39200 × 9}/₁₀₀

= ³⁵²⁸⁰⁰/₁₀₀

= $3528

Thus, Simple Interest = $3528

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 = $5600 + $3528

= $9128

Thus, Amount to be paid = $9128 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 = $5600

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

And, Time (t) = 9 years

Thus, Amount (A)

= $5600 + ($5600 × 7% × 9)

= $5600 + ($5600 ×⁷/₁₀₀ × 9)

= $5600 + (^{5600 × 7 × 9}/₁₀₀)

= $5600 + (^{39200 × 9}/₁₀₀)

= $5600 + (³⁵²⁸⁰⁰/₁₀₀)

= $5600 + $3528 = $9128

Thus, Amount (A) to be paid = $9128 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 $5600, the simple interest in 1 year

= ⁷/₁₀₀ × 5600

= ^{7 × 5600}/₁₀₀

= ³⁹²⁰⁰/₁₀₀ = $392

Thus, simple interest for 1 year = $392

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $392 × 9 = $3528

Thus, Simple Interest (SI) = $3528

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5600 + $3528

= $9128

Thus, Amount to be paid = $9128 Answer

Similar Questions

(1) Mary took a loan of $4100 at the rate of 10% simple interest per annum. If he paid an amount of $7790 to clear the loan, then find the time period of the loan.

(2) Margaret took a loan of $6700 at the rate of 9% simple interest per annum. If he paid an amount of $12127 to clear the loan, then find the time period of the loan.

(3) Calculate the amount due after 10 years if John borrowed a sum of $5200 at a rate of 8% simple interest.

(4) Calculate the amount due if Thomas borrowed a sum of $3800 at 6% simple interest for 3 years.

(5) Calculate the amount due if John borrowed a sum of $3200 at 10% simple interest for 3 years.

(6) Calculate the amount due after 9 years if Patricia borrowed a sum of $5150 at a rate of 7% simple interest.

(7) What amount will be due after 2 years if Robert borrowed a sum of $3050 at a 9% simple interest?

(8) Linda took a loan of $4700 at the rate of 7% simple interest per annum. If he paid an amount of $7990 to clear the loan, then find the time period of the loan.

(9) Calculate the amount due if Robert borrowed a sum of $3100 at 7% simple interest for 3 years.

(10) If Jessica paid $4200 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.