Simple Interest
Math MCQs

Question :    Calculate the amount due if Elizabeth borrowed a sum of $3450 at 4% simple interest for 4 years.

Correct Answer  $4002

Solution & Explanation

Solution

Given,

Principal (P) = $3450

Rate of Simple Interest (SI) = 4%

Time (t) = 4 years

Thus, Amount (A) = ?

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

Thus, here 4% simple interest means, Rate of Simple Interest (SI) is 4% 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) = $3450 × 4% × 4

= $3450 ×⁴/₁₀₀ × 4

= ^{3450 × 4 × 4}/₁₀₀

= ^{13800 × 4}/₁₀₀

= ⁵⁵²⁰⁰/₁₀₀

= $552

Thus, Simple Interest = $552

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 = $3450 + $552

= $4002

Thus, Amount to be paid = $4002 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 = $3450

Rate of Simple Interest (SI) or (R) = 4%

And, Time (t) = 4 years

Thus, Amount (A)

= $3450 + ($3450 × 4% × 4)

= $3450 + ($3450 ×⁴/₁₀₀ × 4)

= $3450 + (^{3450 × 4 × 4}/₁₀₀)

= $3450 + (^{13800 × 4}/₁₀₀)

= $3450 + (⁵⁵²⁰⁰/₁₀₀)

= $3450 + $552 = $4002

Thus, Amount (A) to be paid = $4002 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 4%

This, means, $4 per $100 per year

∵ For $100, the simple interest for 1 year = $4

∴ For $1, the simple interest for 1 year = ⁴/₁₀₀

∴ For $3450, the simple interest in 1 year

= ⁴/₁₀₀ × 3450

= ^{4 × 3450}/₁₀₀

= ¹³⁸⁰⁰/₁₀₀ = $138

Thus, simple interest for 1 year = $138

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $138 × 4 = $552

Thus, Simple Interest (SI) = $552

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3450 + $552

= $4002

Thus, Amount to be paid = $4002 Answer

Similar Questions

(1) Find the amount to be paid if Charles borrowed a sum of $5900 at 5% simple interest for 7 years.

(2) If Sarah paid $4158 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

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

(4) What amount does Susan have to pay after 5 years if he takes a loan of $3650 at 2% simple interest?

(5) Mark took a loan of $6800 at the rate of 7% simple interest per annum. If he paid an amount of $11560 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due after 9 years if Linda borrowed a sum of $5350 at a rate of 9% simple interest.

(7) Charles took a loan of $5800 at the rate of 7% simple interest per annum. If he paid an amount of $9048 to clear the loan, then find the time period of the loan.

(8) Calculate the amount due after 10 years if Charles borrowed a sum of $5900 at a rate of 4% simple interest.

(9) Calculate the amount due if Robert borrowed a sum of $3100 at 6% simple interest for 4 years.

(10) Betty took a loan of $6500 at the rate of 10% simple interest per annum. If he paid an amount of $11050 to clear the loan, then find the time period of the loan.