Simple Interest
Math MCQs

Question :  ( 1 of 10 )  Calculate the amount due after 10 years if Susan borrowed a sum of $5650 at a rate of 8% simple interest.

Correct Answer  $10170

Solution & Explanation

Solution

Given,

Principal (P) = $5650

Rate of Simple Interest (SI) = 8%

Time (t) = 10 years

Thus, Amount (A) = ?

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

Thus, here 8% simple interest means, Rate of Simple Interest (SI) is 8% 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 × 8% × 10

= $5650 ×⁸/₁₀₀ × 10

= ^{5650 × 8 × 10}/₁₀₀

= ^{45200 × 10}/₁₀₀

= ⁴⁵²⁰⁰⁰/₁₀₀

= $4520

Thus, Simple Interest = $4520

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 + $4520

= $10170

Thus, Amount to be paid = $10170 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) = 8%

And, Time (t) = 10 years

Thus, Amount (A)

= $5650 + ($5650 × 8% × 10)

= $5650 + ($5650 ×⁸/₁₀₀ × 10)

= $5650 + (^{5650 × 8 × 10}/₁₀₀)

= $5650 + (^{45200 × 10}/₁₀₀)

= $5650 + (⁴⁵²⁰⁰⁰/₁₀₀)

= $5650 + $4520 = $10170

Thus, Amount (A) to be paid = $10170 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 8%

This, means, $8 per $100 per year

∵ For $100, the simple interest for 1 year = $8

∴ For $1, the simple interest for 1 year = ⁸/₁₀₀

∴ For $5650, the simple interest in 1 year

= ⁸/₁₀₀ × 5650

= ^{8 × 5650}/₁₀₀

= ⁴⁵²⁰⁰/₁₀₀ = $452

Thus, simple interest for 1 year = $452

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $452 × 10 = $4520

Thus, Simple Interest (SI) = $4520

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5650 + $4520

= $10170

Thus, Amount to be paid = $10170 Answer

Similar Questions

(1) Lisa took a loan of $6100 at the rate of 9% simple interest per annum. If he paid an amount of $10492 to clear the loan, then find the time period of the loan.

(2) Find the amount to be paid if Christopher borrowed a sum of $6000 at 6% simple interest for 7 years.

(3) Charles took a loan of $5800 at the rate of 10% simple interest per annum. If he paid an amount of $10440 to clear the loan, then find the time period of the loan.

(4) Calculate the amount due after 10 years if David borrowed a sum of $5400 at a rate of 9% simple interest.

(5) Calculate the amount due if Richard borrowed a sum of $3600 at 6% simple interest for 3 years.

(6) Robert took a loan of $4200 at the rate of 9% simple interest per annum. If he paid an amount of $7602 to clear the loan, then find the time period of the loan.

(7) What amount does Jessica have to pay after 6 years if he takes a loan of $3750 at 6% simple interest?

(8) Robert took a loan of $4200 at the rate of 8% simple interest per annum. If he paid an amount of $6216 to clear the loan, then find the time period of the loan.

(9) In how much time a principal of $3000 will amount to $3180 at a simple interest of 3% per annum?

(10) What amount does Sarah have to pay after 6 years if he takes a loan of $3850 at 8% simple interest?