Simple Interest
Math MCQs

Question :  ( 1 of 10 )  Calculate the amount due after 10 years if Elizabeth borrowed a sum of $5450 at a rate of 7% simple interest.

Correct Answer  $9265

Solution & Explanation

Solution

Given,

Principal (P) = $5450

Rate of Simple Interest (SI) = 7%

Time (t) = 10 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) = $5450 × 7% × 10

= $5450 ×⁷/₁₀₀ × 10

= ^{5450 × 7 × 10}/₁₀₀

= ^{38150 × 10}/₁₀₀

= ³⁸¹⁵⁰⁰/₁₀₀

= $3815

Thus, Simple Interest = $3815

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 = $5450 + $3815

= $9265

Thus, Amount to be paid = $9265 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 = $5450

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

And, Time (t) = 10 years

Thus, Amount (A)

= $5450 + ($5450 × 7% × 10)

= $5450 + ($5450 ×⁷/₁₀₀ × 10)

= $5450 + (^{5450 × 7 × 10}/₁₀₀)

= $5450 + (^{38150 × 10}/₁₀₀)

= $5450 + (³⁸¹⁵⁰⁰/₁₀₀)

= $5450 + $3815 = $9265

Thus, Amount (A) to be paid = $9265 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 $5450, the simple interest in 1 year

= ⁷/₁₀₀ × 5450

= ^{7 × 5450}/₁₀₀

= ³⁸¹⁵⁰/₁₀₀ = $381.5

Thus, simple interest for 1 year = $381.5

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $381.5 × 10 = $3815

Thus, Simple Interest (SI) = $3815

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5450 + $3815

= $9265

Thus, Amount to be paid = $9265 Answer

Similar Questions

(1) Calculate the amount due after 9 years if Linda borrowed a sum of $5350 at a rate of 3% simple interest.

(2) Calculate the amount due after 9 years if Mary borrowed a sum of $5050 at a rate of 9% simple interest.

(3) Calculate the amount due if Jessica borrowed a sum of $3750 at 3% simple interest for 4 years.

(4) What amount does John have to pay after 6 years if he takes a loan of $3200 at 6% simple interest?

(5) Calculate the amount due if David borrowed a sum of $3400 at 2% simple interest for 3 years.

(6) Calculate the amount due after 9 years if James borrowed a sum of $5000 at a rate of 2% simple interest.

(7) Calculate the amount due after 10 years if Susan borrowed a sum of $5650 at a rate of 8% simple interest.

(8) Christopher had to pay $4240 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(9) Calculate the amount due if Charles borrowed a sum of $3900 at 3% simple interest for 3 years.

(10) Calculate the amount due if Joseph borrowed a sum of $3700 at 7% simple interest for 3 years.