Simple Interest
Math MCQs

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

Correct Answer  $4898

Solution & Explanation

Solution

Given,

Principal (P) = $3950

Rate of Simple Interest (SI) = 6%

Time (t) = 4 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) = $3950 × 6% × 4

= $3950 ×⁶/₁₀₀ × 4

= ^{3950 × 6 × 4}/₁₀₀

= ^{23700 × 4}/₁₀₀

= ⁹⁴⁸⁰⁰/₁₀₀

= $948

Thus, Simple Interest = $948

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 = $3950 + $948

= $4898

Thus, Amount to be paid = $4898 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 = $3950

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

And, Time (t) = 4 years

Thus, Amount (A)

= $3950 + ($3950 × 6% × 4)

= $3950 + ($3950 ×⁶/₁₀₀ × 4)

= $3950 + (^{3950 × 6 × 4}/₁₀₀)

= $3950 + (^{23700 × 4}/₁₀₀)

= $3950 + (⁹⁴⁸⁰⁰/₁₀₀)

= $3950 + $948 = $4898

Thus, Amount (A) to be paid = $4898 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 $3950, the simple interest in 1 year

= ⁶/₁₀₀ × 3950

= ^{6 × 3950}/₁₀₀

= ²³⁷⁰⁰/₁₀₀ = $237

Thus, simple interest for 1 year = $237

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $237 × 4 = $948

Thus, Simple Interest (SI) = $948

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3950 + $948

= $4898

Thus, Amount to be paid = $4898 Answer

Similar Questions

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

(2) Calculate the amount due after 9 years if Joseph borrowed a sum of $5700 at a rate of 9% simple interest.

(3) Nancy took a loan of $6300 at the rate of 7% simple interest per annum. If he paid an amount of $10269 to clear the loan, then find the time period of the loan.

(4) How much loan did Jessica borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $6612.5 to clear it?

(5) Sandra took a loan of $6900 at the rate of 10% simple interest per annum. If he paid an amount of $12420 to clear the loan, then find the time period of the loan.

(6) In how much time a principal of $3200 will amount to $3520 at a simple interest of 2% per annum?

(7) Calculate the amount due if Robert borrowed a sum of $3100 at 3% simple interest for 3 years.

(8) Calculate the amount due if Joseph borrowed a sum of $3700 at 9% simple interest for 4 years.

(9) Christopher took a loan of $6000 at the rate of 6% simple interest per annum. If he paid an amount of $9600 to clear the loan, then find the time period of the loan.

(10) Barbara took a loan of $5100 at the rate of 9% simple interest per annum. If he paid an amount of $7854 to clear the loan, then find the time period of the loan.