Simple Interest
Math MCQs

Question :    Find the amount to be paid if Susan borrowed a sum of $5650 at 4% simple interest for 7 years.

Correct Answer  $7232

Solution & Explanation

Solution

Given,

Principal (P) = $5650

Rate of Simple Interest (SI) = 4%

Time (t) = 7 years

Thus, Amount (A) = ?

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

Thus, here 4% simple interest means, Rate of Simple Interest (SI) is 4% 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) = $5650 × 4% × 7

= $5650 ×⁴/₁₀₀ × 7

= ^{5650 × 4 × 7}/₁₀₀

= ^{22600 × 7}/₁₀₀

= ¹⁵⁸²⁰⁰/₁₀₀

= $1582

Thus, Simple Interest = $1582

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 = $5650 + $1582

= $7232

Thus, Amount to be paid = $7232 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 = $5650

Rate of Simple Interest (SI) or (R) = 4%

And, Time (t) = 7 years

Thus, Amount (A)

= $5650 + ($5650 × 4% × 7)

= $5650 + ($5650 ×⁴/₁₀₀ × 7)

= $5650 + (^{5650 × 4 × 7}/₁₀₀)

= $5650 + (^{22600 × 7}/₁₀₀)

= $5650 + (¹⁵⁸²⁰⁰/₁₀₀)

= $5650 + $1582 = $7232

Thus, Amount (A) to be paid = $7232 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 4%

This, means, $4 per $100 per year

∵ For $100, the simple interest for 1 year = $4

∴ For $1, the simple interest for 1 year = ⁴/₁₀₀

∴ For $5650, the simple interest in 1 year

= ⁴/₁₀₀ × 5650

= ^{4 × 5650}/₁₀₀

= ²²⁶⁰⁰/₁₀₀ = $226

Thus, simple interest for 1 year = $226

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $226 × 7 = $1582

Thus, Simple Interest (SI) = $1582

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5650 + $1582

= $7232

Thus, Amount to be paid = $7232 Answer

Similar Questions

(1) What amount does Jennifer have to pay after 5 years if he takes a loan of $3250 at 5% simple interest?

(2) Calculate the amount due if Joseph borrowed a sum of $3700 at 2% simple interest for 4 years.

(3) What amount does Elizabeth have to pay after 5 years if he takes a loan of $3450 at 9% simple interest?

(4) How much loan did Jennifer borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $6300 to clear it?

(5) Karen took a loan of $5900 at the rate of 10% simple interest per annum. If he paid an amount of $10030 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due after 10 years if Richard borrowed a sum of $5600 at a rate of 10% simple interest.

(7) Calculate the amount due if Karen borrowed a sum of $3950 at 3% simple interest for 3 years.

(8) Joseph took a loan of $5400 at the rate of 8% simple interest per annum. If he paid an amount of $7992 to clear the loan, then find the time period of the loan.

(9) Calculate the amount due if Sarah borrowed a sum of $3850 at 6% simple interest for 4 years.

(10) Calculate the amount due after 10 years if Patricia borrowed a sum of $5150 at a rate of 5% simple interest.