Simple Interest
Math MCQs

Question :    What amount does Mary have to pay after 6 years if he takes a loan of $3050 at 4% simple interest?

Correct Answer  $3782

Solution & Explanation

Solution

Given,

Principal (P) = $3050

Rate of Simple Interest (SI) = 4%

Time (t) = 6 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) = $3050 × 4% × 6

= $3050 ×⁴/₁₀₀ × 6

= ^{3050 × 4 × 6}/₁₀₀

= ^{12200 × 6}/₁₀₀

= ⁷³²⁰⁰/₁₀₀

= $732

Thus, Simple Interest = $732

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 = $3050 + $732

= $3782

Thus, Amount to be paid = $3782 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 = $3050

Rate of Simple Interest (SI) or (R) = 4%

And, Time (t) = 6 years

Thus, Amount (A)

= $3050 + ($3050 × 4% × 6)

= $3050 + ($3050 ×⁴/₁₀₀ × 6)

= $3050 + (^{3050 × 4 × 6}/₁₀₀)

= $3050 + (^{12200 × 6}/₁₀₀)

= $3050 + (⁷³²⁰⁰/₁₀₀)

= $3050 + $732 = $3782

Thus, Amount (A) to be paid = $3782 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 $3050, the simple interest in 1 year

= ⁴/₁₀₀ × 3050

= ^{4 × 3050}/₁₀₀

= ¹²²⁰⁰/₁₀₀ = $122

Thus, simple interest for 1 year = $122

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $122 × 6 = $732

Thus, Simple Interest (SI) = $732

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3050 + $732

= $3782

Thus, Amount to be paid = $3782 Answer

Similar Questions

(1) Matthew took a loan of $6400 at the rate of 6% simple interest per annum. If he paid an amount of $10240 to clear the loan, then find the time period of the loan.

(2) Find the amount to be paid if Susan borrowed a sum of $5650 at 7% simple interest for 7 years.

(3) Calculate the amount due after 9 years if Mary borrowed a sum of $5050 at a rate of 10% simple interest.

(4) Find the amount to be paid if Jessica borrowed a sum of $5750 at 7% simple interest for 8 years.

(5) Calculate the amount due if Patricia borrowed a sum of $3150 at 6% simple interest for 3 years.

(6) Calculate the amount due after 10 years if Charles borrowed a sum of $5900 at a rate of 4% simple interest.

(7) Joseph had to pay $4255 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(8) Find the amount to be paid if Robert borrowed a sum of $5100 at 2% simple interest for 8 years.

(9) Calculate the amount due after 10 years if Joseph borrowed a sum of $5700 at a rate of 3% simple interest.

(10) What amount will be due after 2 years if William borrowed a sum of $3250 at a 4% simple interest?