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) What amount will be due after 2 years if Paul borrowed a sum of $3850 at a 8% simple interest?

(2) What amount does Charles have to pay after 6 years if he takes a loan of $3900 at 7% simple interest?

(3) How much loan did Ronald borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $9375 to clear it?

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

(5) How much loan did Richard borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $6440 to clear it?

(6) Calculate the amount due if Karen borrowed a sum of $3950 at 4% simple interest for 3 years.

(7) What amount does Robert have to pay after 5 years if he takes a loan of $3100 at 5% simple interest?

(8) Calculate the amount due after 10 years if James borrowed a sum of $5000 at a rate of 10% simple interest.

(9) In how much time a principal of $3150 will amount to $3780 at a simple interest of 4% per annum?

(10) Charles took a loan of $5800 at the rate of 6% simple interest per annum. If he paid an amount of $7888 to clear the loan, then find the time period of the loan.