Simple Interest
Math MCQs

Question :    Find the amount to be paid if John borrowed a sum of $5200 at 10% simple interest for 8 years.

Correct Answer  $9360

Solution & Explanation

Solution

Given,

Principal (P) = $5200

Rate of Simple Interest (SI) = 10%

Time (t) = 8 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% × 8

= $5200 ×¹⁰/₁₀₀ × 8

= ^{5200 × 10 × 8}/₁₀₀

= ^{52000 × 8}/₁₀₀

= ⁴¹⁶⁰⁰⁰/₁₀₀

= $4160

Thus, Simple Interest = $4160

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 + $4160

= $9360

Thus, Amount to be paid = $9360 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) = 8 years

Thus, Amount (A)

= $5200 + ($5200 × 10% × 8)

= $5200 + ($5200 ×¹⁰/₁₀₀ × 8)

= $5200 + (^{5200 × 10 × 8}/₁₀₀)

= $5200 + (^{52000 × 8}/₁₀₀)

= $5200 + (⁴¹⁶⁰⁰⁰/₁₀₀)

= $5200 + $4160 = $9360

Thus, Amount (A) to be paid = $9360 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 8 years

= Simple interest for 1 year × 8

= $520 × 8 = $4160

Thus, Simple Interest (SI) = $4160

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5200 + $4160

= $9360

Thus, Amount to be paid = $9360 Answer

Similar Questions

(1) Calculate the amount due if Joseph borrowed a sum of $3700 at 3% simple interest for 4 years.

(2) David took a loan of $4800 at the rate of 7% simple interest per annum. If he paid an amount of $8160 to clear the loan, then find the time period of the loan.

(3) Find the amount to be paid if Thomas borrowed a sum of $5800 at 2% simple interest for 8 years.

(4) Robert took a loan of $4200 at the rate of 10% simple interest per annum. If he paid an amount of $7140 to clear the loan, then find the time period of the loan.

(5) Find the amount to be paid if Michael borrowed a sum of $5300 at 8% simple interest for 8 years.

(6) Calculate the amount due after 10 years if Patricia borrowed a sum of $5150 at a rate of 8% simple interest.

(7) Anthony had to pay $4558 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(8) Michael took a loan of $4600 at the rate of 10% simple interest per annum. If he paid an amount of $7360 to clear the loan, then find the time period of the loan.

(9) Lisa took a loan of $6100 at the rate of 10% simple interest per annum. If he paid an amount of $11590 to clear the loan, then find the time period of the loan.

(10) What amount will be due after 2 years if Joshua borrowed a sum of $3950 at a 5% simple interest?