Simple Interest
Math MCQs

Question :    Find the amount to be paid if Richard borrowed a sum of $5600 at 10% simple interest for 7 years.

Correct Answer  $9520

Solution & Explanation

Solution

Given,

Principal (P) = $5600

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) = $5600 × 10% × 7

= $5600 ×¹⁰/₁₀₀ × 7

= ^{5600 × 10 × 7}/₁₀₀

= ^{56000 × 7}/₁₀₀

= ³⁹²⁰⁰⁰/₁₀₀

= $3920

Thus, Simple Interest = $3920

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 = $5600 + $3920

= $9520

Thus, Amount to be paid = $9520 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 = $5600

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

And, Time (t) = 7 years

Thus, Amount (A)

= $5600 + ($5600 × 10% × 7)

= $5600 + ($5600 ×¹⁰/₁₀₀ × 7)

= $5600 + (^{5600 × 10 × 7}/₁₀₀)

= $5600 + (^{56000 × 7}/₁₀₀)

= $5600 + (³⁹²⁰⁰⁰/₁₀₀)

= $5600 + $3920 = $9520

Thus, Amount (A) to be paid = $9520 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 $5600, the simple interest in 1 year

= ¹⁰/₁₀₀ × 5600

= ^{10 × 5600}/₁₀₀

= ⁵⁶⁰⁰⁰/₁₀₀ = $560

Thus, simple interest for 1 year = $560

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $560 × 7 = $3920

Thus, Simple Interest (SI) = $3920

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5600 + $3920

= $9520

Thus, Amount to be paid = $9520 Answer

Similar Questions

(1) How much loan did Nancy borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $7072.5 to clear it?

(2) What amount will be due after 2 years if David borrowed a sum of $3200 at a 10% simple interest?

(3) Calculate the amount due if Jennifer borrowed a sum of $3250 at 8% simple interest for 3 years.

(4) If Donald paid $4860 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(5) Mary took a loan of $4100 at the rate of 10% simple interest per annum. If he paid an amount of $7380 to clear the loan, then find the time period of the loan.

(6) Find the amount to be paid if Richard borrowed a sum of $5600 at 7% simple interest for 8 years.

(7) What amount does Robert have to pay after 6 years if he takes a loan of $3100 at 4% simple interest?

(8) What amount does Elizabeth have to pay after 6 years if he takes a loan of $3450 at 2% simple interest?

(9) Joseph took a loan of $5400 at the rate of 6% simple interest per annum. If he paid an amount of $7668 to clear the loan, then find the time period of the loan.

(10) Margaret took a loan of $6700 at the rate of 8% simple interest per annum. If he paid an amount of $10988 to clear the loan, then find the time period of the loan.