Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Jennifer borrowed a sum of $5250 at a rate of 3% simple interest.

Correct Answer  $6825

Solution & Explanation

Solution

Given,

Principal (P) = $5250

Rate of Simple Interest (SI) = 3%

Time (t) = 10 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) = $5250 × 3% × 10

= $5250 ׳/₁₀₀ × 10

= ^{5250 × 3 × 10}/₁₀₀

= ^{15750 × 10}/₁₀₀

= ¹⁵⁷⁵⁰⁰/₁₀₀

= $1575

Thus, Simple Interest = $1575

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 + $1575

= $6825

Thus, Amount to be paid = $6825 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) = 3%

And, Time (t) = 10 years

Thus, Amount (A)

= $5250 + ($5250 × 3% × 10)

= $5250 + ($5250 ׳/₁₀₀ × 10)

= $5250 + (^{5250 × 3 × 10}/₁₀₀)

= $5250 + (^{15750 × 10}/₁₀₀)

= $5250 + (¹⁵⁷⁵⁰⁰/₁₀₀)

= $5250 + $1575 = $6825

Thus, Amount (A) to be paid = $6825 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 $5250, the simple interest in 1 year

= ³/₁₀₀ × 5250

= ^{3 × 5250}/₁₀₀

= ¹⁵⁷⁵⁰/₁₀₀ = $157.5

Thus, simple interest for 1 year = $157.5

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $157.5 × 10 = $1575

Thus, Simple Interest (SI) = $1575

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5250 + $1575

= $6825

Thus, Amount to be paid = $6825 Answer

Similar Questions

(1) Find the amount to be paid if Joseph borrowed a sum of $5700 at 10% simple interest for 8 years.

(2) What amount does Richard have to pay after 6 years if he takes a loan of $3600 at 3% simple interest?

(3) Michael took a loan of $4600 at the rate of 6% simple interest per annum. If he paid an amount of $6808 to clear the loan, then find the time period of the loan.

(4) In how much time a principal of $3100 will amount to $3596 at a simple interest of 4% per annum?

(5) Calculate the amount due after 9 years if Patricia borrowed a sum of $5150 at a rate of 6% simple interest.

(6) Find the amount to be paid if William borrowed a sum of $5500 at 10% simple interest for 7 years.

(7) How much loan did Sharon borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $8525 to clear it?

(8) How much loan did Sandra borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $7417.5 to clear it?

(9) What amount does Thomas have to pay after 5 years if he takes a loan of $3800 at 5% simple interest?

(10) Betty took a loan of $6500 at the rate of 6% simple interest per annum. If he paid an amount of $9620 to clear the loan, then find the time period of the loan.