Simple Interest
Math MCQs

Question :    What amount does Barbara have to pay after 5 years if he takes a loan of $3550 at 9% simple interest?

Correct Answer  $5147.5

Solution & Explanation

Solution

Given,

Principal (P) = $3550

Rate of Simple Interest (SI) = 9%

Time (t) = 5 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) = $3550 × 9% × 5

= $3550 ×⁹/₁₀₀ × 5

= ^{3550 × 9 × 5}/₁₀₀

= ^{31950 × 5}/₁₀₀

= ¹⁵⁹⁷⁵⁰/₁₀₀

= $1597.5

Thus, Simple Interest = $1597.5

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 = $3550 + $1597.5

= $5147.5

Thus, Amount to be paid = $5147.5 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 = $3550

Rate of Simple Interest (SI) or (R) = 9%

And, Time (t) = 5 years

Thus, Amount (A)

= $3550 + ($3550 × 9% × 5)

= $3550 + ($3550 ×⁹/₁₀₀ × 5)

= $3550 + (^{3550 × 9 × 5}/₁₀₀)

= $3550 + (^{31950 × 5}/₁₀₀)

= $3550 + (¹⁵⁹⁷⁵⁰/₁₀₀)

= $3550 + $1597.5 = $5147.5

Thus, Amount (A) to be paid = $5147.5 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 $3550, the simple interest in 1 year

= ⁹/₁₀₀ × 3550

= ^{9 × 3550}/₁₀₀

= ³¹⁹⁵⁰/₁₀₀ = $319.5

Thus, simple interest for 1 year = $319.5

Therefore, simple interest for 5 years

= Simple interest for 1 year × 5

= $319.5 × 5 = $1597.5

Thus, Simple Interest (SI) = $1597.5

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3550 + $1597.5

= $5147.5

Thus, Amount to be paid = $5147.5 Answer

Similar Questions

(1) How much loan did Jessica borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $6325 to clear it?

(2) Barbara took a loan of $5100 at the rate of 8% simple interest per annum. If he paid an amount of $8772 to clear the loan, then find the time period of the loan.

(3) Calculate the amount due if Elizabeth borrowed a sum of $3450 at 3% simple interest for 4 years.

(4) If Joseph paid $3996 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(5) How much loan did Charles borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $6785 to clear it?

(6) What amount does Linda have to pay after 6 years if he takes a loan of $3350 at 8% simple interest?

(7) If Mark paid $4752 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(8) Jennifer took a loan of $4500 at the rate of 6% simple interest per annum. If he paid an amount of $6930 to clear the loan, then find the time period of the loan.

(9) What amount does Susan have to pay after 6 years if he takes a loan of $3650 at 10% simple interest?

(10) Patricia took a loan of $4300 at the rate of 8% simple interest per annum. If he paid an amount of $7396 to clear the loan, then find the time period of the loan.