Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if Richard borrowed a sum of $5600 at a rate of 3% simple interest.

Correct Answer  $7112

Solution & Explanation

Solution

Given,

Principal (P) = $5600

Rate of Simple Interest (SI) = 3%

Time (t) = 9 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) = $5600 × 3% × 9

= $5600 ׳/₁₀₀ × 9

= ^{5600 × 3 × 9}/₁₀₀

= ^{16800 × 9}/₁₀₀

= ¹⁵¹²⁰⁰/₁₀₀

= $1512

Thus, Simple Interest = $1512

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 = $5600 + $1512

= $7112

Thus, Amount to be paid = $7112 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 = $5600

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

And, Time (t) = 9 years

Thus, Amount (A)

= $5600 + ($5600 × 3% × 9)

= $5600 + ($5600 ׳/₁₀₀ × 9)

= $5600 + (^{5600 × 3 × 9}/₁₀₀)

= $5600 + (^{16800 × 9}/₁₀₀)

= $5600 + (¹⁵¹²⁰⁰/₁₀₀)

= $5600 + $1512 = $7112

Thus, Amount (A) to be paid = $7112 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 $5600, the simple interest in 1 year

= ³/₁₀₀ × 5600

= ^{3 × 5600}/₁₀₀

= ¹⁶⁸⁰⁰/₁₀₀ = $168

Thus, simple interest for 1 year = $168

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $168 × 9 = $1512

Thus, Simple Interest (SI) = $1512

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5600 + $1512

= $7112

Thus, Amount to be paid = $7112 Answer

Similar Questions

(1) What amount will be due after 2 years if Joshua borrowed a sum of $3950 at a 4% simple interest?

(2) How much loan did Jacob borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $9200 to clear it?

(3) Calculate the amount due if Mary borrowed a sum of $3050 at 7% simple interest for 3 years.

(4) Calculate the amount due if David borrowed a sum of $3400 at 7% simple interest for 4 years.

(5) Calculate the amount due after 9 years if William borrowed a sum of $5500 at a rate of 2% simple interest.

(6) How much loan did Kimberly borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $8312.5 to clear it?

(7) Find the amount to be paid if Christopher borrowed a sum of $6000 at 4% simple interest for 8 years.

(8) In how much time a principal of $3000 will amount to $3120 at a simple interest of 2% per annum?

(9) Nancy took a loan of $6300 at the rate of 7% simple interest per annum. If he paid an amount of $9387 to clear the loan, then find the time period of the loan.

(10) Joseph took a loan of $5400 at the rate of 10% simple interest per annum. If he paid an amount of $10260 to clear the loan, then find the time period of the loan.