Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if Jennifer borrowed a sum of $5250 at a rate of 10% simple interest.

Correct Answer  $9975

Solution & Explanation

Solution

Given,

Principal (P) = $5250

Rate of Simple Interest (SI) = 10%

Time (t) = 9 years

Thus, Amount (A) = ?

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

Thus, here 10% simple interest means, Rate of Simple Interest (SI) is 10% 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) = $5250 × 10% × 9

= $5250 ×¹⁰/₁₀₀ × 9

= ^{5250 × 10 × 9}/₁₀₀

= ^{52500 × 9}/₁₀₀

= ⁴⁷²⁵⁰⁰/₁₀₀

= $4725

Thus, Simple Interest = $4725

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 = $5250 + $4725

= $9975

Thus, Amount to be paid = $9975 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 = $5250

Rate of Simple Interest (SI) or (R) = 10%

And, Time (t) = 9 years

Thus, Amount (A)

= $5250 + ($5250 × 10% × 9)

= $5250 + ($5250 ×¹⁰/₁₀₀ × 9)

= $5250 + (^{5250 × 10 × 9}/₁₀₀)

= $5250 + (^{52500 × 9}/₁₀₀)

= $5250 + (⁴⁷²⁵⁰⁰/₁₀₀)

= $5250 + $4725 = $9975

Thus, Amount (A) to be paid = $9975 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 10%

This, means, $10 per $100 per year

∵ For $100, the simple interest for 1 year = $10

∴ For $1, the simple interest for 1 year = ¹⁰/₁₀₀

∴ For $5250, the simple interest in 1 year

= ¹⁰/₁₀₀ × 5250

= ^{10 × 5250}/₁₀₀

= ⁵²⁵⁰⁰/₁₀₀ = $525

Thus, simple interest for 1 year = $525

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $525 × 9 = $4725

Thus, Simple Interest (SI) = $4725

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5250 + $4725

= $9975

Thus, Amount to be paid = $9975 Answer

Similar Questions

(1) How much loan did Kenneth borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $8750 to clear it?

(2) How much loan did David borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $6210 to clear it?

(3) If Kenneth paid $5400 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(4) How much loan did Joseph borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $7125 to clear it?

(5) Charles had to pay $4368 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(6) How much loan did Matthew borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $7130 to clear it?

(7) Betty took a loan of $6500 at the rate of 7% simple interest per annum. If he paid an amount of $11050 to clear the loan, then find the time period of the loan.

(8) Find the amount to be paid if Robert borrowed a sum of $5100 at 7% simple interest for 7 years.

(9) Calculate the amount due after 9 years if Sarah borrowed a sum of $5850 at a rate of 2% simple interest.

(10) What amount does Elizabeth have to pay after 6 years if he takes a loan of $3450 at 4% simple interest?