Simple Interest
Math MCQs

Question :  ( 1 of 10 )  What amount does Barbara have to pay after 5 years if he takes a loan of $3550 at 10% simple interest?

Correct Answer  $5325

Solution & Explanation

Solution

Given,

Principal (P) = $3550

Rate of Simple Interest (SI) = 10%

Time (t) = 5 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) = $3550 × 10% × 5

= $3550 ×¹⁰/₁₀₀ × 5

= ^{3550 × 10 × 5}/₁₀₀

= ^{35500 × 5}/₁₀₀

= ¹⁷⁷⁵⁰⁰/₁₀₀

= $1775

Thus, Simple Interest = $1775

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 = $3550 + $1775

= $5325

Thus, Amount to be paid = $5325 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 = $3550

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

And, Time (t) = 5 years

Thus, Amount (A)

= $3550 + ($3550 × 10% × 5)

= $3550 + ($3550 ×¹⁰/₁₀₀ × 5)

= $3550 + (^{3550 × 10 × 5}/₁₀₀)

= $3550 + (^{35500 × 5}/₁₀₀)

= $3550 + (¹⁷⁷⁵⁰⁰/₁₀₀)

= $3550 + $1775 = $5325

Thus, Amount (A) to be paid = $5325 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 $3550, the simple interest in 1 year

= ¹⁰/₁₀₀ × 3550

= ^{10 × 3550}/₁₀₀

= ³⁵⁵⁰⁰/₁₀₀ = $355

Thus, simple interest for 1 year = $355

Therefore, simple interest for 5 years

= Simple interest for 1 year × 5

= $355 × 5 = $1775

Thus, Simple Interest (SI) = $1775

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3550 + $1775

= $5325

Thus, Amount to be paid = $5325 Answer

Similar Questions

(1) Calculate the amount due if Charles borrowed a sum of $3900 at 8% simple interest for 3 years.

(2) What amount does Linda have to pay after 6 years if he takes a loan of $3350 at 3% simple interest?

(3) Mark took a loan of $6800 at the rate of 10% simple interest per annum. If he paid an amount of $13600 to clear the loan, then find the time period of the loan.

(4) What amount does Richard have to pay after 5 years if he takes a loan of $3600 at 10% simple interest?

(5) Sandra took a loan of $6900 at the rate of 6% simple interest per annum. If he paid an amount of $11040 to clear the loan, then find the time period of the loan.

(6) Find the amount to be paid if David borrowed a sum of $5400 at 10% simple interest for 8 years.

(7) Calculate the amount due after 9 years if Karen borrowed a sum of $5950 at a rate of 6% simple interest.

(8) Calculate the amount due after 9 years if Charles borrowed a sum of $5900 at a rate of 5% simple interest.

(9) Find the amount to be paid if Thomas borrowed a sum of $5800 at 9% simple interest for 7 years.

(10) Find the amount to be paid if Sarah borrowed a sum of $5850 at 10% simple interest for 7 years.