Simple Interest
Math MCQs

Question :    Find the amount to be paid if Linda borrowed a sum of $5350 at 3% simple interest for 7 years.

Correct Answer  $6473.5

Solution & Explanation

Solution

Given,

Principal (P) = $5350

Rate of Simple Interest (SI) = 3%

Time (t) = 7 years

Thus, Amount (A) = ?

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

Thus, here 3% simple interest means, Rate of Simple Interest (SI) is 3% 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) = $5350 × 3% × 7

= $5350 ׳/₁₀₀ × 7

= ^{5350 × 3 × 7}/₁₀₀

= ^{16050 × 7}/₁₀₀

= ¹¹²³⁵⁰/₁₀₀

= $1123.5

Thus, Simple Interest = $1123.5

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 = $5350 + $1123.5

= $6473.5

Thus, Amount to be paid = $6473.5 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 = $5350

Rate of Simple Interest (SI) or (R) = 3%

And, Time (t) = 7 years

Thus, Amount (A)

= $5350 + ($5350 × 3% × 7)

= $5350 + ($5350 ׳/₁₀₀ × 7)

= $5350 + (^{5350 × 3 × 7}/₁₀₀)

= $5350 + (^{16050 × 7}/₁₀₀)

= $5350 + (¹¹²³⁵⁰/₁₀₀)

= $5350 + $1123.5 = $6473.5

Thus, Amount (A) to be paid = $6473.5 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 3%

This, means, $3 per $100 per year

∵ For $100, the simple interest for 1 year = $3

∴ For $1, the simple interest for 1 year = ³/₁₀₀

∴ For $5350, the simple interest in 1 year

= ³/₁₀₀ × 5350

= ^{3 × 5350}/₁₀₀

= ¹⁶⁰⁵⁰/₁₀₀ = $160.5

Thus, simple interest for 1 year = $160.5

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $160.5 × 7 = $1123.5

Thus, Simple Interest (SI) = $1123.5

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5350 + $1123.5

= $6473.5

Thus, Amount to be paid = $6473.5 Answer

Similar Questions

(1) Joshua had to pay $5341 in order to furnish the loan taken 3 years before. If the rate of simple interest was 3% then find the sum borrowed.

(2) How much loan did Paul borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $7370 to clear it?

(3) Calculate the amount due if Richard borrowed a sum of $3600 at 10% simple interest for 3 years.

(4) Barbara had to pay $3976 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(5) Ashley had to pay $4823 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(6) Find the amount to be paid if William borrowed a sum of $5500 at 10% simple interest for 7 years.

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

(9) Find the amount to be paid if Thomas borrowed a sum of $5800 at 5% simple interest for 8 years.

(10) Calculate the amount due after 10 years if John borrowed a sum of $5200 at a rate of 7% simple interest.