Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if Michael borrowed a sum of $5300 at a rate of 4% simple interest.

Correct Answer  $7208

Solution & Explanation

Solution

Given,

Principal (P) = $5300

Rate of Simple Interest (SI) = 4%

Time (t) = 9 years

Thus, Amount (A) = ?

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

Thus, here 4% simple interest means, Rate of Simple Interest (SI) is 4% 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 × 4% × 9

= $5300 ×⁴/₁₀₀ × 9

= ^{5300 × 4 × 9}/₁₀₀

= ^{21200 × 9}/₁₀₀

= ¹⁹⁰⁸⁰⁰/₁₀₀

= $1908

Thus, Simple Interest = $1908

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 + $1908

= $7208

Thus, Amount to be paid = $7208 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) = 4%

And, Time (t) = 9 years

Thus, Amount (A)

= $5300 + ($5300 × 4% × 9)

= $5300 + ($5300 ×⁴/₁₀₀ × 9)

= $5300 + (^{5300 × 4 × 9}/₁₀₀)

= $5300 + (^{21200 × 9}/₁₀₀)

= $5300 + (¹⁹⁰⁸⁰⁰/₁₀₀)

= $5300 + $1908 = $7208

Thus, Amount (A) to be paid = $7208 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 4%

This, means, $4 per $100 per year

∵ For $100, the simple interest for 1 year = $4

∴ For $1, the simple interest for 1 year = ⁴/₁₀₀

∴ For $5300, the simple interest in 1 year

= ⁴/₁₀₀ × 5300

= ^{4 × 5300}/₁₀₀

= ²¹²⁰⁰/₁₀₀ = $212

Thus, simple interest for 1 year = $212

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $212 × 9 = $1908

Thus, Simple Interest (SI) = $1908

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5300 + $1908

= $7208

Thus, Amount to be paid = $7208 Answer

Similar Questions

(1) 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?

(2) Sandra had to pay $4717 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(3) Find the amount to be paid if Michael borrowed a sum of $5300 at 5% simple interest for 7 years.

(4) Calculate the amount due if Elizabeth borrowed a sum of $3450 at 8% simple interest for 3 years.

(5) Calculate the amount due after 9 years if David borrowed a sum of $5400 at a rate of 2% simple interest.

(6) What amount does Barbara have to pay after 6 years if he takes a loan of $3550 at 10% simple interest?

(7) If Christopher paid $4800 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(8) If Elizabeth borrowed $3450 from a bank at a rate of 2% simple interest per annum then find the amount to be paid after 2 years.

(9) Find the amount to be paid if Charles borrowed a sum of $5900 at 2% simple interest for 8 years.

(10) What amount does Susan have to pay after 5 years if he takes a loan of $3650 at 8% simple interest?