Simple Interest
Math MCQs

Question :  ( 1 of 10 )  Calculate the amount due after 9 years if Mary borrowed a sum of $5050 at a rate of 10% simple interest.

Correct Answer  $9595

Solution & Explanation

Solution

Given,

Principal (P) = $5050

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) = $5050 × 10% × 9

= $5050 ×¹⁰/₁₀₀ × 9

= ^{5050 × 10 × 9}/₁₀₀

= ^{50500 × 9}/₁₀₀

= ⁴⁵⁴⁵⁰⁰/₁₀₀

= $4545

Thus, Simple Interest = $4545

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 = $5050 + $4545

= $9595

Thus, Amount to be paid = $9595 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 = $5050

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

And, Time (t) = 9 years

Thus, Amount (A)

= $5050 + ($5050 × 10% × 9)

= $5050 + ($5050 ×¹⁰/₁₀₀ × 9)

= $5050 + (^{5050 × 10 × 9}/₁₀₀)

= $5050 + (^{50500 × 9}/₁₀₀)

= $5050 + (⁴⁵⁴⁵⁰⁰/₁₀₀)

= $5050 + $4545 = $9595

Thus, Amount (A) to be paid = $9595 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 $5050, the simple interest in 1 year

= ¹⁰/₁₀₀ × 5050

= ^{10 × 5050}/₁₀₀

= ⁵⁰⁵⁰⁰/₁₀₀ = $505

Thus, simple interest for 1 year = $505

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $505 × 9 = $4545

Thus, Simple Interest (SI) = $4545

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5050 + $4545

= $9595

Thus, Amount to be paid = $9595 Answer

Similar Questions

(1) What amount does Elizabeth have to pay after 5 years if he takes a loan of $3450 at 5% simple interest?

(2) Sarah took a loan of $5700 at the rate of 7% simple interest per annum. If he paid an amount of $8892 to clear the loan, then find the time period of the loan.

(3) What amount will be due after 2 years if James borrowed a sum of $3000 at a 7% simple interest?

(4) Jennifer took a loan of $4500 at the rate of 10% simple interest per annum. If he paid an amount of $7650 to clear the loan, then find the time period of the loan.

(5) In how much time a principal of $3000 will amount to $3480 at a simple interest of 4% per annum?

(6) What amount does Mary have to pay after 5 years if he takes a loan of $3050 at 10% simple interest?

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

(8) Calculate the amount due after 10 years if Mary borrowed a sum of $5050 at a rate of 8% simple interest.

(9) What amount does Joseph have to pay after 6 years if he takes a loan of $3700 at 9% simple interest?

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