Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Linda borrowed a sum of $5350 at a rate of 4% simple interest.

Correct Answer  $7490

Solution & Explanation

Solution

Given,

Principal (P) = $5350

Rate of Simple Interest (SI) = 4%

Time (t) = 10 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) = $5350 × 4% × 10

= $5350 ×⁴/₁₀₀ × 10

= ^{5350 × 4 × 10}/₁₀₀

= ^{21400 × 10}/₁₀₀

= ²¹⁴⁰⁰⁰/₁₀₀

= $2140

Thus, Simple Interest = $2140

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 = $5350 + $2140

= $7490

Thus, Amount to be paid = $7490 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 = $5350

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

And, Time (t) = 10 years

Thus, Amount (A)

= $5350 + ($5350 × 4% × 10)

= $5350 + ($5350 ×⁴/₁₀₀ × 10)

= $5350 + (^{5350 × 4 × 10}/₁₀₀)

= $5350 + (^{21400 × 10}/₁₀₀)

= $5350 + (²¹⁴⁰⁰⁰/₁₀₀)

= $5350 + $2140 = $7490

Thus, Amount (A) to be paid = $7490 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 $5350, the simple interest in 1 year

= ⁴/₁₀₀ × 5350

= ^{4 × 5350}/₁₀₀

= ²¹⁴⁰⁰/₁₀₀ = $214

Thus, simple interest for 1 year = $214

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $214 × 10 = $2140

Thus, Simple Interest (SI) = $2140

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5350 + $2140

= $7490

Thus, Amount to be paid = $7490 Answer

Similar Questions

(1) Mark took a loan of $6800 at the rate of 7% simple interest per annum. If he paid an amount of $10608 to clear the loan, then find the time period of the loan.

(2) Charles took a loan of $5800 at the rate of 7% simple interest per annum. If he paid an amount of $9860 to clear the loan, then find the time period of the loan.

(3) Karen took a loan of $5900 at the rate of 6% simple interest per annum. If he paid an amount of $9440 to clear the loan, then find the time period of the loan.

(4) Kimberly had to pay $4929 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(5) Charles took a loan of $5800 at the rate of 9% simple interest per annum. If he paid an amount of $8932 to clear the loan, then find the time period of the loan.

(6) What amount will be due after 2 years if Paul borrowed a sum of $3850 at a 9% simple interest?

(7) Christopher took a loan of $6000 at the rate of 7% simple interest per annum. If he paid an amount of $10200 to clear the loan, then find the time period of the loan.

(8) What amount does Sarah have to pay after 5 years if he takes a loan of $3850 at 5% simple interest?

(9) Karen took a loan of $5900 at the rate of 6% simple interest per annum. If he paid an amount of $8024 to clear the loan, then find the time period of the loan.

(10) What amount does Barbara have to pay after 6 years if he takes a loan of $3550 at 6% simple interest?