Simple Interest
Math MCQs

Question :  ( 1 of 10 )  Find the amount to be paid if Barbara borrowed a sum of $5550 at 10% simple interest for 8 years.

Correct Answer  $9990

Solution & Explanation

Solution

Given,

Principal (P) = $5550

Rate of Simple Interest (SI) = 10%

Time (t) = 8 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) = $5550 × 10% × 8

= $5550 ×¹⁰/₁₀₀ × 8

= ^{5550 × 10 × 8}/₁₀₀

= ^{55500 × 8}/₁₀₀

= ⁴⁴⁴⁰⁰⁰/₁₀₀

= $4440

Thus, Simple Interest = $4440

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 = $5550 + $4440

= $9990

Thus, Amount to be paid = $9990 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 = $5550

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

And, Time (t) = 8 years

Thus, Amount (A)

= $5550 + ($5550 × 10% × 8)

= $5550 + ($5550 ×¹⁰/₁₀₀ × 8)

= $5550 + (^{5550 × 10 × 8}/₁₀₀)

= $5550 + (^{55500 × 8}/₁₀₀)

= $5550 + (⁴⁴⁴⁰⁰⁰/₁₀₀)

= $5550 + $4440 = $9990

Thus, Amount (A) to be paid = $9990 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 $5550, the simple interest in 1 year

= ¹⁰/₁₀₀ × 5550

= ^{10 × 5550}/₁₀₀

= ⁵⁵⁵⁰⁰/₁₀₀ = $555

Thus, simple interest for 1 year = $555

Therefore, simple interest for 8 years

= Simple interest for 1 year × 8

= $555 × 8 = $4440

Thus, Simple Interest (SI) = $4440

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5550 + $4440

= $9990

Thus, Amount to be paid = $9990 Answer

Similar Questions

(1) Lisa took a loan of $6100 at the rate of 8% simple interest per annum. If he paid an amount of $10980 to clear the loan, then find the time period of the loan.

(2) Calculate the amount due if Michael borrowed a sum of $3300 at 4% simple interest for 4 years.

(3) What amount does Barbara have to pay after 5 years if he takes a loan of $3550 at 3% simple interest?

(4) Elizabeth took a loan of $4900 at the rate of 10% simple interest per annum. If he paid an amount of $8820 to clear the loan, then find the time period of the loan.

(5) What amount does Barbara have to pay after 6 years if he takes a loan of $3550 at 7% simple interest?

(6) Calculate the amount due after 10 years if Christopher borrowed a sum of $6000 at a rate of 10% simple interest.

(7) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 5% simple interest for 8 years.

(8) Calculate the amount due after 10 years if Sarah borrowed a sum of $5850 at a rate of 8% simple interest.

(9) Calculate the amount due after 10 years if Thomas borrowed a sum of $5800 at a rate of 5% simple interest.

(10) Jennifer took a loan of $4500 at the rate of 6% simple interest per annum. If he paid an amount of $6390 to clear the loan, then find the time period of the loan.