Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if John borrowed a sum of $5200 at a rate of 10% simple interest.

Correct Answer  $10400

Solution & Explanation

Solution

Given,

Principal (P) = $5200

Rate of Simple Interest (SI) = 10%

Time (t) = 10 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) = $5200 × 10% × 10

= $5200 ×¹⁰/₁₀₀ × 10

= ^{5200 × 10 × 10}/₁₀₀

= ^{52000 × 10}/₁₀₀

= ⁵²⁰⁰⁰⁰/₁₀₀

= $5200

Thus, Simple Interest = $5200

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 = $5200 + $5200

= $10400

Thus, Amount to be paid = $10400 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 = $5200

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

And, Time (t) = 10 years

Thus, Amount (A)

= $5200 + ($5200 × 10% × 10)

= $5200 + ($5200 ×¹⁰/₁₀₀ × 10)

= $5200 + (^{5200 × 10 × 10}/₁₀₀)

= $5200 + (^{52000 × 10}/₁₀₀)

= $5200 + (⁵²⁰⁰⁰⁰/₁₀₀)

= $5200 + $5200 = $10400

Thus, Amount (A) to be paid = $10400 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 $5200, the simple interest in 1 year

= ¹⁰/₁₀₀ × 5200

= ^{10 × 5200}/₁₀₀

= ⁵²⁰⁰⁰/₁₀₀ = $520

Thus, simple interest for 1 year = $520

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $520 × 10 = $5200

Thus, Simple Interest (SI) = $5200

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5200 + $5200

= $10400

Thus, Amount to be paid = $10400 Answer

Similar Questions

(1) Calculate the amount due if Mary borrowed a sum of $3050 at 7% simple interest for 3 years.

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

(3) What amount does Robert have to pay after 6 years if he takes a loan of $3100 at 5% simple interest?

(4) If Susan borrowed $3650 from a bank at a rate of 2% simple interest per annum then find the amount to be paid after 2 years.

(5) In how much time a principal of $3000 will amount to $3120 at a simple interest of 2% per annum?

(6) What amount does Joseph have to pay after 5 years if he takes a loan of $3700 at 3% simple interest?

(7) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 4% simple interest for 7 years.

(8) Robert took a loan of $4200 at the rate of 8% simple interest per annum. If he paid an amount of $7560 to clear the loan, then find the time period of the loan.

(9) Calculate the amount due if Jennifer borrowed a sum of $3250 at 3% simple interest for 4 years.

(10) Calculate the amount due after 9 years if Linda borrowed a sum of $5350 at a rate of 6% simple interest.