Simple Interest
Math MCQs

Question :  ( 1 of 10 )  Find the amount to be paid if Linda borrowed a sum of $5350 at 9% simple interest for 7 years.

Correct Answer  $8720.5

Solution & Explanation

Solution

Given,

Principal (P) = $5350

Rate of Simple Interest (SI) = 9%

Time (t) = 7 years

Thus, Amount (A) = ?

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

Thus, here 9% simple interest means, Rate of Simple Interest (SI) is 9% 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 × 9% × 7

= $5350 ×⁹/₁₀₀ × 7

= ^{5350 × 9 × 7}/₁₀₀

= ^{48150 × 7}/₁₀₀

= ³³⁷⁰⁵⁰/₁₀₀

= $3370.5

Thus, Simple Interest = $3370.5

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 + $3370.5

= $8720.5

Thus, Amount to be paid = $8720.5 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) = 9%

And, Time (t) = 7 years

Thus, Amount (A)

= $5350 + ($5350 × 9% × 7)

= $5350 + ($5350 ×⁹/₁₀₀ × 7)

= $5350 + (^{5350 × 9 × 7}/₁₀₀)

= $5350 + (^{48150 × 7}/₁₀₀)

= $5350 + (³³⁷⁰⁵⁰/₁₀₀)

= $5350 + $3370.5 = $8720.5

Thus, Amount (A) to be paid = $8720.5 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 9%

This, means, $9 per $100 per year

∵ For $100, the simple interest for 1 year = $9

∴ For $1, the simple interest for 1 year = ⁹/₁₀₀

∴ For $5350, the simple interest in 1 year

= ⁹/₁₀₀ × 5350

= ^{9 × 5350}/₁₀₀

= ⁴⁸¹⁵⁰/₁₀₀ = $481.5

Thus, simple interest for 1 year = $481.5

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $481.5 × 7 = $3370.5

Thus, Simple Interest (SI) = $3370.5

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5350 + $3370.5

= $8720.5

Thus, Amount to be paid = $8720.5 Answer

Similar Questions

(1) Calculate the amount due if Susan borrowed a sum of $3650 at 6% simple interest for 4 years.

(2) Find the amount to be paid if John borrowed a sum of $5200 at 3% simple interest for 7 years.

(3) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 6% simple interest for 8 years.

(4) In how much time a principal of $3150 will amount to $3465 at a simple interest of 5% per annum?

(5) What amount does Thomas have to pay after 5 years if he takes a loan of $3800 at 9% simple interest?

(6) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 9% simple interest for 8 years.

(7) How much loan did Richard borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $6160 to clear it?

(8) Calculate the amount due after 10 years if William borrowed a sum of $5500 at a rate of 7% simple interest.

(9) Calculate the amount due after 9 years if Patricia borrowed a sum of $5150 at a rate of 2% simple interest.

(10) Find the amount to be paid if Susan borrowed a sum of $5650 at 6% simple interest for 7 years.