Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if Michael borrowed a sum of $5300 at a rate of 9% simple interest.

Correct Answer  $9593

Solution & Explanation

Solution

Given,

Principal (P) = $5300

Rate of Simple Interest (SI) = 9%

Time (t) = 9 years

Thus, Amount (A) = ?

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

Thus, here 9% simple interest means, Rate of Simple Interest (SI) is 9% 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) = $5300 × 9% × 9

= $5300 ×⁹/₁₀₀ × 9

= ^{5300 × 9 × 9}/₁₀₀

= ^{47700 × 9}/₁₀₀

= ⁴²⁹³⁰⁰/₁₀₀

= $4293

Thus, Simple Interest = $4293

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 = $5300 + $4293

= $9593

Thus, Amount to be paid = $9593 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 = $5300

Rate of Simple Interest (SI) or (R) = 9%

And, Time (t) = 9 years

Thus, Amount (A)

= $5300 + ($5300 × 9% × 9)

= $5300 + ($5300 ×⁹/₁₀₀ × 9)

= $5300 + (^{5300 × 9 × 9}/₁₀₀)

= $5300 + (^{47700 × 9}/₁₀₀)

= $5300 + (⁴²⁹³⁰⁰/₁₀₀)

= $5300 + $4293 = $9593

Thus, Amount (A) to be paid = $9593 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 9%

This, means, $9 per $100 per year

∵ For $100, the simple interest for 1 year = $9

∴ For $1, the simple interest for 1 year = ⁹/₁₀₀

∴ For $5300, the simple interest in 1 year

= ⁹/₁₀₀ × 5300

= ^{9 × 5300}/₁₀₀

= ⁴⁷⁷⁰⁰/₁₀₀ = $477

Thus, simple interest for 1 year = $477

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $477 × 9 = $4293

Thus, Simple Interest (SI) = $4293

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5300 + $4293

= $9593

Thus, Amount to be paid = $9593 Answer

Similar Questions

(1) Mary took a loan of $4100 at the rate of 9% simple interest per annum. If he paid an amount of $6683 to clear the loan, then find the time period of the loan.

(2) What amount does Linda have to pay after 5 years if he takes a loan of $3350 at 8% simple interest?

(3) Find the amount to be paid if Sarah borrowed a sum of $5850 at 6% simple interest for 7 years.

(4) Susan took a loan of $5300 at the rate of 9% simple interest per annum. If he paid an amount of $10070 to clear the loan, then find the time period of the loan.

(5) Robert took a loan of $4200 at the rate of 10% simple interest per annum. If he paid an amount of $7980 to clear the loan, then find the time period of the loan.

(6) Robert took a loan of $4200 at the rate of 9% simple interest per annum. If he paid an amount of $6468 to clear the loan, then find the time period of the loan.

(7) In how much time a principal of $3200 will amount to $3584 at a simple interest of 4% per annum?

(8) How much loan did Linda borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $5885 to clear it?

(9) Calculate the amount due after 10 years if Barbara borrowed a sum of $5550 at a rate of 10% simple interest.

(10) Calculate the amount due if Joseph borrowed a sum of $3700 at 2% simple interest for 3 years.