Simple Interest
Math MCQs

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

Correct Answer  $6840

Solution & Explanation

Solution

Given,

Principal (P) = $6000

Rate of Simple Interest (SI) = 2%

Time (t) = 7 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) = $6000 × 2% × 7

= $6000 ײ/₁₀₀ × 7

= ^{6000 × 2 × 7}/₁₀₀

= ^{12000 × 7}/₁₀₀

= ⁸⁴⁰⁰⁰/₁₀₀

= $840

Thus, Simple Interest = $840

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 = $6000 + $840

= $6840

Thus, Amount to be paid = $6840 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 = $6000

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

And, Time (t) = 7 years

Thus, Amount (A)

= $6000 + ($6000 × 2% × 7)

= $6000 + ($6000 ײ/₁₀₀ × 7)

= $6000 + (^{6000 × 2 × 7}/₁₀₀)

= $6000 + (^{12000 × 7}/₁₀₀)

= $6000 + (⁸⁴⁰⁰⁰/₁₀₀)

= $6000 + $840 = $6840

Thus, Amount (A) to be paid = $6840 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 $6000, the simple interest in 1 year

= ²/₁₀₀ × 6000

= ^{2 × 6000}/₁₀₀

= ¹²⁰⁰⁰/₁₀₀ = $120

Thus, simple interest for 1 year = $120

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $120 × 7 = $840

Thus, Simple Interest (SI) = $840

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $6000 + $840

= $6840

Thus, Amount to be paid = $6840 Answer

Similar Questions

(1) Robert had to pay $3286 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(2) What amount will be due after 2 years if Anthony borrowed a sum of $3650 at a 7% simple interest?

(3) What amount does Christopher have to pay after 6 years if he takes a loan of $4000 at 8% simple interest?

(4) Nancy took a loan of $6300 at the rate of 7% simple interest per annum. If he paid an amount of $10710 to clear the loan, then find the time period of the loan.

(5) How much loan did Ashley borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $7532.5 to clear it?

(6) Find the amount to be paid if Patricia borrowed a sum of $5150 at 4% simple interest for 8 years.

(7) In how much time a principal of $3200 will amount to $3584 at a simple interest of 4% per annum?

(8) What amount does Jennifer have to pay after 6 years if he takes a loan of $3250 at 8% simple interest?

(9) Calculate the amount due if Sarah borrowed a sum of $3850 at 4% simple interest for 3 years.

(10) Charles had to pay $4251 in order to furnish the loan taken 3 years before. If the rate of simple interest was 3% then find the sum borrowed.