Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Thomas borrowed a sum of $5800 at a rate of 6% simple interest.

Correct Answer  $9280

Solution & Explanation

Solution

Given,

Principal (P) = $5800

Rate of Simple Interest (SI) = 6%

Time (t) = 10 years

Thus, Amount (A) = ?

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

Thus, here 6% simple interest means, Rate of Simple Interest (SI) is 6% 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) = $5800 × 6% × 10

= $5800 ×⁶/₁₀₀ × 10

= ^{5800 × 6 × 10}/₁₀₀

= ^{34800 × 10}/₁₀₀

= ³⁴⁸⁰⁰⁰/₁₀₀

= $3480

Thus, Simple Interest = $3480

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 = $5800 + $3480

= $9280

Thus, Amount to be paid = $9280 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 = $5800

Rate of Simple Interest (SI) or (R) = 6%

And, Time (t) = 10 years

Thus, Amount (A)

= $5800 + ($5800 × 6% × 10)

= $5800 + ($5800 ×⁶/₁₀₀ × 10)

= $5800 + (^{5800 × 6 × 10}/₁₀₀)

= $5800 + (^{34800 × 10}/₁₀₀)

= $5800 + (³⁴⁸⁰⁰⁰/₁₀₀)

= $5800 + $3480 = $9280

Thus, Amount (A) to be paid = $9280 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 6%

This, means, $6 per $100 per year

∵ For $100, the simple interest for 1 year = $6

∴ For $1, the simple interest for 1 year = ⁶/₁₀₀

∴ For $5800, the simple interest in 1 year

= ⁶/₁₀₀ × 5800

= ^{6 × 5800}/₁₀₀

= ³⁴⁸⁰⁰/₁₀₀ = $348

Thus, simple interest for 1 year = $348

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $348 × 10 = $3480

Thus, Simple Interest (SI) = $3480

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5800 + $3480

= $9280

Thus, Amount to be paid = $9280 Answer

Similar Questions

(1) Patricia had to pay $3622.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(2) Mark took a loan of $6800 at the rate of 10% simple interest per annum. If he paid an amount of $11560 to clear the loan, then find the time period of the loan.

(3) How much loan did Brian borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $8280 to clear it?

(4) Linda took a loan of $4700 at the rate of 8% simple interest per annum. If he paid an amount of $6956 to clear the loan, then find the time period of the loan.

(5) Mary took a loan of $4100 at the rate of 9% simple interest per annum. If he paid an amount of $7421 to clear the loan, then find the time period of the loan.

(6) If Michael paid $3564 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(7) Find the amount to be paid if Richard borrowed a sum of $5600 at 6% simple interest for 8 years.

(8) How much loan did Charles borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $7375 to clear it?

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

(10) Find the amount to be paid if Patricia borrowed a sum of $5150 at 2% simple interest for 8 years.