Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Jennifer borrowed a sum of $5250 at a rate of 9% simple interest.

Correct Answer  $9975

Solution & Explanation

Solution

Given,

Principal (P) = $5250

Rate of Simple Interest (SI) = 9%

Time (t) = 10 years

Thus, Amount (A) = ?

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

Thus, here 9% simple interest means, Rate of Simple Interest (SI) is 9% 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) = $5250 × 9% × 10

= $5250 ×⁹/₁₀₀ × 10

= ^{5250 × 9 × 10}/₁₀₀

= ^{47250 × 10}/₁₀₀

= ⁴⁷²⁵⁰⁰/₁₀₀

= $4725

Thus, Simple Interest = $4725

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 = $5250 + $4725

= $9975

Thus, Amount to be paid = $9975 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 = $5250

Rate of Simple Interest (SI) or (R) = 9%

And, Time (t) = 10 years

Thus, Amount (A)

= $5250 + ($5250 × 9% × 10)

= $5250 + ($5250 ×⁹/₁₀₀ × 10)

= $5250 + (^{5250 × 9 × 10}/₁₀₀)

= $5250 + (^{47250 × 10}/₁₀₀)

= $5250 + (⁴⁷²⁵⁰⁰/₁₀₀)

= $5250 + $4725 = $9975

Thus, Amount (A) to be paid = $9975 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 9%

This, means, $9 per $100 per year

∵ For $100, the simple interest for 1 year = $9

∴ For $1, the simple interest for 1 year = ⁹/₁₀₀

∴ For $5250, the simple interest in 1 year

= ⁹/₁₀₀ × 5250

= ^{9 × 5250}/₁₀₀

= ⁴⁷²⁵⁰/₁₀₀ = $472.5

Thus, simple interest for 1 year = $472.5

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $472.5 × 10 = $4725

Thus, Simple Interest (SI) = $4725

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5250 + $4725

= $9975

Thus, Amount to be paid = $9975 Answer

Similar Questions

(1) Calculate the amount due if James borrowed a sum of $3000 at 9% simple interest for 3 years.

(2) Find the amount to be paid if Robert borrowed a sum of $5100 at 5% simple interest for 7 years.

(3) Calculate the amount due if Elizabeth borrowed a sum of $3450 at 3% simple interest for 3 years.

(4) Find the amount to be paid if William borrowed a sum of $5500 at 7% simple interest for 8 years.

(5) What amount does Mary have to pay after 5 years if he takes a loan of $3050 at 6% simple interest?

(6) Calculate the amount due after 10 years if Patricia borrowed a sum of $5150 at a rate of 5% simple interest.

(7) If Steven paid $4968 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(8) How much loan did Donald borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $7150 to clear it?

(9) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 9% simple interest for 8 years.

(10) What amount does Robert have to pay after 6 years if he takes a loan of $3100 at 8% simple interest?