Simple Interest
Math MCQs

Question :    Calculate the amount due if Linda borrowed a sum of $3350 at 2% simple interest for 3 years.

Correct Answer  $3551

Solution & Explanation

Solution

Given,

Principal (P) = $3350

Rate of Simple Interest (SI) = 2%

Time (t) = 3 years

Thus, Amount (A) = ?

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

Thus, here 2% simple interest means, Rate of Simple Interest (SI) is 2% 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) = $3350 × 2% × 3

= $3350 ײ/₁₀₀ × 3

= ^{3350 × 2 × 3}/₁₀₀

= ^{6700 × 3}/₁₀₀

= ²⁰¹⁰⁰/₁₀₀

= $201

Thus, Simple Interest = $201

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 = $3350 + $201

= $3551

Thus, Amount to be paid = $3551 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 = $3350

Rate of Simple Interest (SI) or (R) = 2%

And, Time (t) = 3 years

Thus, Amount (A)

= $3350 + ($3350 × 2% × 3)

= $3350 + ($3350 ײ/₁₀₀ × 3)

= $3350 + (^{3350 × 2 × 3}/₁₀₀)

= $3350 + (^{6700 × 3}/₁₀₀)

= $3350 + (²⁰¹⁰⁰/₁₀₀)

= $3350 + $201 = $3551

Thus, Amount (A) to be paid = $3551 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 2%

This, means, $2 per $100 per year

∵ For $100, the simple interest for 1 year = $2

∴ For $1, the simple interest for 1 year = ²/₁₀₀

∴ For $3350, the simple interest in 1 year

= ²/₁₀₀ × 3350

= ^{2 × 3350}/₁₀₀

= ⁶⁷⁰⁰/₁₀₀ = $67

Thus, simple interest for 1 year = $67

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $67 × 3 = $201

Thus, Simple Interest (SI) = $201

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3350 + $201

= $3551

Thus, Amount to be paid = $3551 Answer

Similar Questions

(1) Calculate the amount due if Elizabeth borrowed a sum of $3450 at 7% simple interest for 4 years.

(2) John took a loan of $4400 at the rate of 7% simple interest per annum. If he paid an amount of $6248 to clear the loan, then find the time period of the loan.

(3) Calculate the amount due after 9 years if Christopher borrowed a sum of $6000 at a rate of 6% simple interest.

(4) Find the amount to be paid if Michael borrowed a sum of $5300 at 3% simple interest for 8 years.

(5) How much loan did Ashley borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $7860 to clear it?

(6) What amount does Thomas have to pay after 5 years if he takes a loan of $3800 at 9% simple interest?

(7) How much loan did George borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $8395 to clear it?

(8) How much loan did Andrew borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $7820 to clear it?

(9) Charles took a loan of $5800 at the rate of 9% simple interest per annum. If he paid an amount of $10498 to clear the loan, then find the time period of the loan.

(10) Find the amount to be paid if Richard borrowed a sum of $5600 at 5% simple interest for 7 years.