Simple Interest
Math MCQs

Question :    What amount does Thomas have to pay after 6 years if he takes a loan of $3800 at 10% simple interest?

Correct Answer  $6080

Solution & Explanation

Solution

Given,

Principal (P) = $3800

Rate of Simple Interest (SI) = 10%

Time (t) = 6 years

Thus, Amount (A) = ?

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

Thus, here 10% simple interest means, Rate of Simple Interest (SI) is 10% 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) = $3800 × 10% × 6

= $3800 ×¹⁰/₁₀₀ × 6

= ^{3800 × 10 × 6}/₁₀₀

= ^{38000 × 6}/₁₀₀

= ²²⁸⁰⁰⁰/₁₀₀

= $2280

Thus, Simple Interest = $2280

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 = $3800 + $2280

= $6080

Thus, Amount to be paid = $6080 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 = $3800

Rate of Simple Interest (SI) or (R) = 10%

And, Time (t) = 6 years

Thus, Amount (A)

= $3800 + ($3800 × 10% × 6)

= $3800 + ($3800 ×¹⁰/₁₀₀ × 6)

= $3800 + (^{3800 × 10 × 6}/₁₀₀)

= $3800 + (^{38000 × 6}/₁₀₀)

= $3800 + (²²⁸⁰⁰⁰/₁₀₀)

= $3800 + $2280 = $6080

Thus, Amount (A) to be paid = $6080 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 10%

This, means, $10 per $100 per year

∵ For $100, the simple interest for 1 year = $10

∴ For $1, the simple interest for 1 year = ¹⁰/₁₀₀

∴ For $3800, the simple interest in 1 year

= ¹⁰/₁₀₀ × 3800

= ^{10 × 3800}/₁₀₀

= ³⁸⁰⁰⁰/₁₀₀ = $380

Thus, simple interest for 1 year = $380

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $380 × 6 = $2280

Thus, Simple Interest (SI) = $2280

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3800 + $2280

= $6080

Thus, Amount to be paid = $6080 Answer

Similar Questions

(1) Joseph took a loan of $5400 at the rate of 7% simple interest per annum. If he paid an amount of $8802 to clear the loan, then find the time period of the loan.

(2) Patricia had to pay $3339 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(3) David took a loan of $4800 at the rate of 8% simple interest per annum. If he paid an amount of $7104 to clear the loan, then find the time period of the loan.

(4) Calculate the amount due if Jennifer borrowed a sum of $3250 at 4% simple interest for 3 years.

(5) Matthew took a loan of $6400 at the rate of 9% simple interest per annum. If he paid an amount of $12160 to clear the loan, then find the time period of the loan.

(6) Find the amount to be paid if Linda borrowed a sum of $5350 at 9% simple interest for 7 years.

(7) Christopher took a loan of $6000 at the rate of 9% simple interest per annum. If he paid an amount of $9240 to clear the loan, then find the time period of the loan.

(8) Mary had to pay $3233 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(9) Calculate the amount due after 10 years if Susan borrowed a sum of $5650 at a rate of 6% simple interest.

(10) Matthew took a loan of $6400 at the rate of 9% simple interest per annum. If he paid an amount of $11008 to clear the loan, then find the time period of the loan.