Simple Interest
Math MCQs

Question :    Calculate the amount due if Jennifer borrowed a sum of $3250 at 10% simple interest for 4 years.

Correct Answer  $4550

Solution & Explanation

Solution

Given,

Principal (P) = $3250

Rate of Simple Interest (SI) = 10%

Time (t) = 4 years

Thus, Amount (A) = ?

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

Thus, here 10% simple interest means, Rate of Simple Interest (SI) is 10% 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) = $3250 × 10% × 4

= $3250 ×¹⁰/₁₀₀ × 4

= ^{3250 × 10 × 4}/₁₀₀

= ^{32500 × 4}/₁₀₀

= ¹³⁰⁰⁰⁰/₁₀₀

= $1300

Thus, Simple Interest = $1300

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 = $3250 + $1300

= $4550

Thus, Amount to be paid = $4550 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 = $3250

Rate of Simple Interest (SI) or (R) = 10%

And, Time (t) = 4 years

Thus, Amount (A)

= $3250 + ($3250 × 10% × 4)

= $3250 + ($3250 ×¹⁰/₁₀₀ × 4)

= $3250 + (^{3250 × 10 × 4}/₁₀₀)

= $3250 + (^{32500 × 4}/₁₀₀)

= $3250 + (¹³⁰⁰⁰⁰/₁₀₀)

= $3250 + $1300 = $4550

Thus, Amount (A) to be paid = $4550 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 10%

This, means, $10 per $100 per year

∵ For $100, the simple interest for 1 year = $10

∴ For $1, the simple interest for 1 year = ¹⁰/₁₀₀

∴ For $3250, the simple interest in 1 year

= ¹⁰/₁₀₀ × 3250

= ^{10 × 3250}/₁₀₀

= ³²⁵⁰⁰/₁₀₀ = $325

Thus, simple interest for 1 year = $325

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $325 × 4 = $1300

Thus, Simple Interest (SI) = $1300

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3250 + $1300

= $4550

Thus, Amount to be paid = $4550 Answer

Similar Questions

(1) Barbara took a loan of $5100 at the rate of 8% simple interest per annum. If he paid an amount of $8364 to clear the loan, then find the time period of the loan.

(2) Matthew took a loan of $6400 at the rate of 8% simple interest per annum. If he paid an amount of $9984 to clear the loan, then find the time period of the loan.

(3) If David paid $4080 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(4) How much loan did Joshua borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $8625 to clear it?

(5) Find the amount to be paid if Linda borrowed a sum of $5350 at 8% simple interest for 7 years.

(6) Calculate the amount due if David borrowed a sum of $3400 at 10% simple interest for 4 years.

(7) Calculate the amount due after 9 years if Charles borrowed a sum of $5900 at a rate of 10% simple interest.

(8) Christopher took a loan of $6000 at the rate of 8% simple interest per annum. If he paid an amount of $9840 to clear the loan, then find the time period of the loan.

(9) William took a loan of $5000 at the rate of 7% simple interest per annum. If he paid an amount of $8500 to clear the loan, then find the time period of the loan.

(10) Find the amount to be paid if Michael borrowed a sum of $5300 at 9% simple interest for 7 years.