Simple Interest
Math MCQs

Question :    Find the amount to be paid if Susan borrowed a sum of $5650 at 10% simple interest for 7 years.

Correct Answer  $9605

Solution & Explanation

Solution

Given,

Principal (P) = $5650

Rate of Simple Interest (SI) = 10%

Time (t) = 7 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) = $5650 × 10% × 7

= $5650 ×¹⁰/₁₀₀ × 7

= ^{5650 × 10 × 7}/₁₀₀

= ^{56500 × 7}/₁₀₀

= ³⁹⁵⁵⁰⁰/₁₀₀

= $3955

Thus, Simple Interest = $3955

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 + $3955

= $9605

Thus, Amount to be paid = $9605 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) = 10%

And, Time (t) = 7 years

Thus, Amount (A)

= $5650 + ($5650 × 10% × 7)

= $5650 + ($5650 ×¹⁰/₁₀₀ × 7)

= $5650 + (^{5650 × 10 × 7}/₁₀₀)

= $5650 + (^{56500 × 7}/₁₀₀)

= $5650 + (³⁹⁵⁵⁰⁰/₁₀₀)

= $5650 + $3955 = $9605

Thus, Amount (A) to be paid = $9605 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 $5650, the simple interest in 1 year

= ¹⁰/₁₀₀ × 5650

= ^{10 × 5650}/₁₀₀

= ⁵⁶⁵⁰⁰/₁₀₀ = $565

Thus, simple interest for 1 year = $565

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $565 × 7 = $3955

Thus, Simple Interest (SI) = $3955

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5650 + $3955

= $9605

Thus, Amount to be paid = $9605 Answer

Similar Questions

(1) Calculate the amount due after 9 years if Sarah borrowed a sum of $5850 at a rate of 4% simple interest.

(2) What amount does Linda have to pay after 5 years if he takes a loan of $3350 at 10% simple interest?

(3) What amount will be due after 2 years if Daniel borrowed a sum of $3550 at a 7% simple interest?

(4) What amount does Jessica have to pay after 5 years if he takes a loan of $3750 at 9% simple interest?

(5) John had to pay $3584 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

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

(7) Find the amount to be paid if William borrowed a sum of $5500 at 8% simple interest for 7 years.

(8) Calculate the amount due if Barbara borrowed a sum of $3550 at 8% simple interest for 4 years.

(9) If Patricia paid $3528 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(10) Margaret took a loan of $6700 at the rate of 9% simple interest per annum. If he paid an amount of $10921 to clear the loan, then find the time period of the loan.