Simple Interest
Math MCQs

Question :    Find the amount to be paid if David borrowed a sum of $5400 at 6% simple interest for 7 years.

Correct Answer  $7668

Solution & Explanation

Solution

Given,

Principal (P) = $5400

Rate of Simple Interest (SI) = 6%

Time (t) = 7 years

Thus, Amount (A) = ?

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

Thus, here 6% simple interest means, Rate of Simple Interest (SI) is 6% 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) = $5400 × 6% × 7

= $5400 ×⁶/₁₀₀ × 7

= ^{5400 × 6 × 7}/₁₀₀

= ^{32400 × 7}/₁₀₀

= ²²⁶⁸⁰⁰/₁₀₀

= $2268

Thus, Simple Interest = $2268

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 = $5400 + $2268

= $7668

Thus, Amount to be paid = $7668 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 = $5400

Rate of Simple Interest (SI) or (R) = 6%

And, Time (t) = 7 years

Thus, Amount (A)

= $5400 + ($5400 × 6% × 7)

= $5400 + ($5400 ×⁶/₁₀₀ × 7)

= $5400 + (^{5400 × 6 × 7}/₁₀₀)

= $5400 + (^{32400 × 7}/₁₀₀)

= $5400 + (²²⁶⁸⁰⁰/₁₀₀)

= $5400 + $2268 = $7668

Thus, Amount (A) to be paid = $7668 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 6%

This, means, $6 per $100 per year

∵ For $100, the simple interest for 1 year = $6

∴ For $1, the simple interest for 1 year = ⁶/₁₀₀

∴ For $5400, the simple interest in 1 year

= ⁶/₁₀₀ × 5400

= ^{6 × 5400}/₁₀₀

= ³²⁴⁰⁰/₁₀₀ = $324

Thus, simple interest for 1 year = $324

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $324 × 7 = $2268

Thus, Simple Interest (SI) = $2268

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5400 + $2268

= $7668

Thus, Amount to be paid = $7668 Answer

Similar Questions

(1) Mark took a loan of $6800 at the rate of 6% simple interest per annum. If he paid an amount of $10472 to clear the loan, then find the time period of the loan.

(2) Sarah took a loan of $5700 at the rate of 6% simple interest per annum. If he paid an amount of $8094 to clear the loan, then find the time period of the loan.

(3) Jennifer took a loan of $4500 at the rate of 10% simple interest per annum. If he paid an amount of $8550 to clear the loan, then find the time period of the loan.

(4) Thomas took a loan of $5600 at the rate of 7% simple interest per annum. If he paid an amount of $7952 to clear the loan, then find the time period of the loan.

(5) Calculate the amount due if Karen borrowed a sum of $3950 at 8% simple interest for 4 years.

(6) Find the amount to be paid if Michael borrowed a sum of $5300 at 5% simple interest for 8 years.

(7) What amount will be due after 2 years if Steven borrowed a sum of $3800 at a 7% simple interest?

(8) If David paid $3944 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(9) Thomas took a loan of $5600 at the rate of 6% simple interest per annum. If he paid an amount of $8960 to clear the loan, then find the time period of the loan.

(10) Calculate the amount due after 9 years if Robert borrowed a sum of $5100 at a rate of 10% simple interest.