Simple Interest
Math MCQs

Question :    What amount does Michael have to pay after 5 years if he takes a loan of $3300 at 9% simple interest?

Correct Answer  $4785

Solution & Explanation

Solution

Given,

Principal (P) = $3300

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) = $3300 × 9% × 5

= $3300 ×⁹/₁₀₀ × 5

= ^{3300 × 9 × 5}/₁₀₀

= ^{29700 × 5}/₁₀₀

= ¹⁴⁸⁵⁰⁰/₁₀₀

= $1485

Thus, Simple Interest = $1485

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 = $3300 + $1485

= $4785

Thus, Amount to be paid = $4785 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 = $3300

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

And, Time (t) = 5 years

Thus, Amount (A)

= $3300 + ($3300 × 9% × 5)

= $3300 + ($3300 ×⁹/₁₀₀ × 5)

= $3300 + (^{3300 × 9 × 5}/₁₀₀)

= $3300 + (^{29700 × 5}/₁₀₀)

= $3300 + (¹⁴⁸⁵⁰⁰/₁₀₀)

= $3300 + $1485 = $4785

Thus, Amount (A) to be paid = $4785 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 $3300, the simple interest in 1 year

= ⁹/₁₀₀ × 3300

= ^{9 × 3300}/₁₀₀

= ²⁹⁷⁰⁰/₁₀₀ = $297

Thus, simple interest for 1 year = $297

Therefore, simple interest for 5 years

= Simple interest for 1 year × 5

= $297 × 5 = $1485

Thus, Simple Interest (SI) = $1485

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3300 + $1485

= $4785

Thus, Amount to be paid = $4785 Answer

Similar Questions

(1) Calculate the amount due if Patricia borrowed a sum of $3150 at 7% simple interest for 3 years.

(2) 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.

(3) What amount will be due after 2 years if Richard borrowed a sum of $3300 at a 6% simple interest?

(4) Elizabeth took a loan of $4900 at the rate of 10% simple interest per annum. If he paid an amount of $8330 to clear the loan, then find the time period of the loan.

(5) Mark took a loan of $6800 at the rate of 9% simple interest per annum. If he paid an amount of $12920 to clear the loan, then find the time period of the loan.

(6) How much loan did Daniel borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $7320 to clear it?

(7) Calculate the amount due after 10 years if Mary borrowed a sum of $5050 at a rate of 10% simple interest.

(8) What amount does Linda have to pay after 5 years if he takes a loan of $3350 at 7% simple interest?

(9) Michael took a loan of $4600 at the rate of 6% simple interest per annum. If he paid an amount of $6532 to clear the loan, then find the time period of the loan.

(10) Find the amount to be paid if Jessica borrowed a sum of $5750 at 2% simple interest for 7 years.