Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Linda borrowed a sum of $5350 at a rate of 8% simple interest.

Correct Answer  $9630

Solution & Explanation

Solution

Given,

Principal (P) = $5350

Rate of Simple Interest (SI) = 8%

Time (t) = 10 years

Thus, Amount (A) = ?

The Rate of Interest is always calculated per annum, i.e. per year.

Thus, here 8% simple interest means, Rate of Simple Interest (SI) is 8% 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) = $5350 × 8% × 10

= $5350 ×⁸/₁₀₀ × 10

= ^{5350 × 8 × 10}/₁₀₀

= ^{42800 × 10}/₁₀₀

= ⁴²⁸⁰⁰⁰/₁₀₀

= $4280

Thus, Simple Interest = $4280

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 = $5350 + $4280

= $9630

Thus, Amount to be paid = $9630 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 = $5350

Rate of Simple Interest (SI) or (R) = 8%

And, Time (t) = 10 years

Thus, Amount (A)

= $5350 + ($5350 × 8% × 10)

= $5350 + ($5350 ×⁸/₁₀₀ × 10)

= $5350 + (^{5350 × 8 × 10}/₁₀₀)

= $5350 + (^{42800 × 10}/₁₀₀)

= $5350 + (⁴²⁸⁰⁰⁰/₁₀₀)

= $5350 + $4280 = $9630

Thus, Amount (A) to be paid = $9630 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 8%

This, means, $8 per $100 per year

∵ For $100, the simple interest for 1 year = $8

∴ For $1, the simple interest for 1 year = ⁸/₁₀₀

∴ For $5350, the simple interest in 1 year

= ⁸/₁₀₀ × 5350

= ^{8 × 5350}/₁₀₀

= ⁴²⁸⁰⁰/₁₀₀ = $428

Thus, simple interest for 1 year = $428

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $428 × 10 = $4280

Thus, Simple Interest (SI) = $4280

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5350 + $4280

= $9630

Thus, Amount to be paid = $9630 Answer

Similar Questions

(1) Find the amount to be paid if Jessica borrowed a sum of $5750 at 9% simple interest for 7 years.

(2) Find the amount to be paid if Barbara borrowed a sum of $5550 at 8% simple interest for 7 years.

(3) What amount will be due after 2 years if William borrowed a sum of $3250 at a 9% simple interest?

(4) Margaret had to pay $4741.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 3% then find the sum borrowed.

(5) Find the amount to be paid if Patricia borrowed a sum of $5150 at 10% simple interest for 7 years.

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

(7) Find the amount to be paid if Christopher borrowed a sum of $6000 at 7% simple interest for 7 years.

(8) In how much time a principal of $3050 will amount to $3507.5 at a simple interest of 3% per annum?

(9) What amount does Charles have to pay after 6 years if he takes a loan of $3900 at 4% simple interest?

(10) Calculate the amount due after 10 years if Christopher borrowed a sum of $6000 at a rate of 2% simple interest.