Simple Interest
Math MCQs

Question :    Find the amount to be paid if Thomas borrowed a sum of $5800 at 10% simple interest for 7 years.

Correct Answer  $9860

Solution & Explanation

Solution

Given,

Principal (P) = $5800

Rate of Simple Interest (SI) = 10%

Time (t) = 7 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) = $5800 × 10% × 7

= $5800 ×¹⁰/₁₀₀ × 7

= ^{5800 × 10 × 7}/₁₀₀

= ^{58000 × 7}/₁₀₀

= ⁴⁰⁶⁰⁰⁰/₁₀₀

= $4060

Thus, Simple Interest = $4060

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 = $5800 + $4060

= $9860

Thus, Amount to be paid = $9860 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 = $5800

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

And, Time (t) = 7 years

Thus, Amount (A)

= $5800 + ($5800 × 10% × 7)

= $5800 + ($5800 ×¹⁰/₁₀₀ × 7)

= $5800 + (^{5800 × 10 × 7}/₁₀₀)

= $5800 + (^{58000 × 7}/₁₀₀)

= $5800 + (⁴⁰⁶⁰⁰⁰/₁₀₀)

= $5800 + $4060 = $9860

Thus, Amount (A) to be paid = $9860 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 $5800, the simple interest in 1 year

= ¹⁰/₁₀₀ × 5800

= ^{10 × 5800}/₁₀₀

= ⁵⁸⁰⁰⁰/₁₀₀ = $580

Thus, simple interest for 1 year = $580

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $580 × 7 = $4060

Thus, Simple Interest (SI) = $4060

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5800 + $4060

= $9860

Thus, Amount to be paid = $9860 Answer

Similar Questions

(1) In how much time a principal of $3150 will amount to $3433.5 at a simple interest of 3% per annum?

(2) Christopher took a loan of $6000 at the rate of 7% simple interest per annum. If he paid an amount of $10200 to clear the loan, then find the time period of the loan.

(3) James had to pay $3360 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(4) If David paid $3944 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(5) Find the amount to be paid if Thomas borrowed a sum of $5800 at 5% simple interest for 7 years.

(6) What amount will be due after 2 years if Anthony borrowed a sum of $3650 at a 10% simple interest?

(7) Anthony took a loan of $6600 at the rate of 7% simple interest per annum. If he paid an amount of $9372 to clear the loan, then find the time period of the loan.

(8) Calculate the amount due if Thomas borrowed a sum of $3800 at 7% simple interest for 4 years.

(9) Find the amount to be paid if Robert borrowed a sum of $5100 at 6% simple interest for 8 years.

(10) Barbara took a loan of $5100 at the rate of 9% simple interest per annum. If he paid an amount of $9690 to clear the loan, then find the time period of the loan.