Simple Interest
Math MCQs

Question :    Find the amount to be paid if Charles borrowed a sum of $5900 at 10% simple interest for 8 years.

Correct Answer  $10620

Solution & Explanation

Solution

Given,

Principal (P) = $5900

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) = $5900 × 10% × 8

= $5900 ×¹⁰/₁₀₀ × 8

= ^{5900 × 10 × 8}/₁₀₀

= ^{59000 × 8}/₁₀₀

= ⁴⁷²⁰⁰⁰/₁₀₀

= $4720

Thus, Simple Interest = $4720

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 = $5900 + $4720

= $10620

Thus, Amount to be paid = $10620 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 = $5900

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

And, Time (t) = 8 years

Thus, Amount (A)

= $5900 + ($5900 × 10% × 8)

= $5900 + ($5900 ×¹⁰/₁₀₀ × 8)

= $5900 + (^{5900 × 10 × 8}/₁₀₀)

= $5900 + (^{59000 × 8}/₁₀₀)

= $5900 + (⁴⁷²⁰⁰⁰/₁₀₀)

= $5900 + $4720 = $10620

Thus, Amount (A) to be paid = $10620 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 $5900, the simple interest in 1 year

= ¹⁰/₁₀₀ × 5900

= ^{10 × 5900}/₁₀₀

= ⁵⁹⁰⁰⁰/₁₀₀ = $590

Thus, simple interest for 1 year = $590

Therefore, simple interest for 8 years

= Simple interest for 1 year × 8

= $590 × 8 = $4720

Thus, Simple Interest (SI) = $4720

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5900 + $4720

= $10620

Thus, Amount to be paid = $10620 Answer

Similar Questions

(1) Anthony took a loan of $6600 at the rate of 9% simple interest per annum. If he paid an amount of $11352 to clear the loan, then find the time period of the loan.

(2) Calculate the amount due after 10 years if Barbara borrowed a sum of $5550 at a rate of 4% simple interest.

(3) Calculate the amount due after 10 years if William borrowed a sum of $5500 at a rate of 8% simple interest.

(4) What amount does Mary have to pay after 6 years if he takes a loan of $3050 at 9% simple interest?

(5) Find the amount to be paid if John borrowed a sum of $5200 at 6% simple interest for 8 years.

(6) Elizabeth took a loan of $4900 at the rate of 9% simple interest per annum. If he paid an amount of $9310 to clear the loan, then find the time period of the loan.

(7) What amount does Elizabeth have to pay after 5 years if he takes a loan of $3450 at 10% simple interest?

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

(9) Patricia took a loan of $4300 at the rate of 10% simple interest per annum. If he paid an amount of $7310 to clear the loan, then find the time period of the loan.

(10) What amount does Charles have to pay after 6 years if he takes a loan of $3900 at 7% simple interest?