Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Christopher borrowed a sum of $6000 at a rate of 6% simple interest.

Correct Answer  $9600

Solution & Explanation

Solution

Given,

Principal (P) = $6000

Rate of Simple Interest (SI) = 6%

Time (t) = 10 years

Thus, Amount (A) = ?

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

Thus, here 6% simple interest means, Rate of Simple Interest (SI) is 6% 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) = $6000 × 6% × 10

= $6000 ×⁶/₁₀₀ × 10

= ^{6000 × 6 × 10}/₁₀₀

= ^{36000 × 10}/₁₀₀

= ³⁶⁰⁰⁰⁰/₁₀₀

= $3600

Thus, Simple Interest = $3600

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 = $6000 + $3600

= $9600

Thus, Amount to be paid = $9600 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 = $6000

Rate of Simple Interest (SI) or (R) = 6%

And, Time (t) = 10 years

Thus, Amount (A)

= $6000 + ($6000 × 6% × 10)

= $6000 + ($6000 ×⁶/₁₀₀ × 10)

= $6000 + (^{6000 × 6 × 10}/₁₀₀)

= $6000 + (^{36000 × 10}/₁₀₀)

= $6000 + (³⁶⁰⁰⁰⁰/₁₀₀)

= $6000 + $3600 = $9600

Thus, Amount (A) to be paid = $9600 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 6%

This, means, $6 per $100 per year

∵ For $100, the simple interest for 1 year = $6

∴ For $1, the simple interest for 1 year = ⁶/₁₀₀

∴ For $6000, the simple interest in 1 year

= ⁶/₁₀₀ × 6000

= ^{6 × 6000}/₁₀₀

= ³⁶⁰⁰⁰/₁₀₀ = $360

Thus, simple interest for 1 year = $360

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $360 × 10 = $3600

Thus, Simple Interest (SI) = $3600

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $6000 + $3600

= $9600

Thus, Amount to be paid = $9600 Answer

Similar Questions

(1) Find the amount to be paid if Barbara borrowed a sum of $5550 at 6% simple interest for 8 years.

(2) Barbara took a loan of $5100 at the rate of 8% simple interest per annum. If he paid an amount of $8772 to clear the loan, then find the time period of the loan.

(3) How much loan did Melissa borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $8820 to clear it?

(4) If Sarah paid $4312 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

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

(6) Barbara took a loan of $5100 at the rate of 7% simple interest per annum. If he paid an amount of $7956 to clear the loan, then find the time period of the loan.

(7) James took a loan of $4000 at the rate of 10% simple interest per annum. If he paid an amount of $6800 to clear the loan, then find the time period of the loan.

(8) If Sarah borrowed $3850 from a bank at a rate of 2% simple interest per annum then find the amount to be paid after 2 years.

(9) Calculate the amount due after 10 years if James borrowed a sum of $5000 at a rate of 6% simple interest.

(10) Calculate the amount due after 9 years if Susan borrowed a sum of $5650 at a rate of 8% simple interest.