Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if William borrowed a sum of $5500 at a rate of 3% simple interest.

Correct Answer  $6985

Solution & Explanation

Solution

Given,

Principal (P) = $5500

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) = $5500 × 3% × 9

= $5500 ׳/₁₀₀ × 9

= ^{5500 × 3 × 9}/₁₀₀

= ^{16500 × 9}/₁₀₀

= ¹⁴⁸⁵⁰⁰/₁₀₀

= $1485

Thus, Simple Interest = $1485

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 = $5500 + $1485

= $6985

Thus, Amount to be paid = $6985 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 = $5500

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

And, Time (t) = 9 years

Thus, Amount (A)

= $5500 + ($5500 × 3% × 9)

= $5500 + ($5500 ׳/₁₀₀ × 9)

= $5500 + (^{5500 × 3 × 9}/₁₀₀)

= $5500 + (^{16500 × 9}/₁₀₀)

= $5500 + (¹⁴⁸⁵⁰⁰/₁₀₀)

= $5500 + $1485 = $6985

Thus, Amount (A) to be paid = $6985 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 $5500, the simple interest in 1 year

= ³/₁₀₀ × 5500

= ^{3 × 5500}/₁₀₀

= ¹⁶⁵⁰⁰/₁₀₀ = $165

Thus, simple interest for 1 year = $165

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $165 × 9 = $1485

Thus, Simple Interest (SI) = $1485

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5500 + $1485

= $6985

Thus, Amount to be paid = $6985 Answer

Similar Questions

(1) Christopher took a loan of $6000 at the rate of 10% simple interest per annum. If he paid an amount of $12000 to clear the loan, then find the time period of the loan.

(2) If Robert borrowed $3100 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 years.

(3) How much loan did Ronald borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $9000 to clear it?

(4) In how much time a principal of $3100 will amount to $3720 at a simple interest of 5% per annum?

(5) Robert took a loan of $4200 at the rate of 8% simple interest per annum. If he paid an amount of $7560 to clear the loan, then find the time period of the loan.

(6) Find the amount to be paid if Michael borrowed a sum of $5300 at 6% simple interest for 7 years.

(7) Calculate the amount due after 9 years if William borrowed a sum of $5500 at a rate of 3% simple interest.

(8) Matthew took a loan of $6400 at the rate of 7% simple interest per annum. If he paid an amount of $9536 to clear the loan, then find the time period of the loan.

(9) What amount will be due after 2 years if Joseph borrowed a sum of $3350 at a 7% simple interest?

(10) Richard took a loan of $5200 at the rate of 9% simple interest per annum. If he paid an amount of $9880 to clear the loan, then find the time period of the loan.