Simple Interest
Math MCQs

Question :    Calculate the amount due if Susan borrowed a sum of $3650 at 8% simple interest for 4 years.

Correct Answer  $4818

Solution & Explanation

Solution

Given,

Principal (P) = $3650

Rate of Simple Interest (SI) = 8%

Time (t) = 4 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) = $3650 × 8% × 4

= $3650 ×⁸/₁₀₀ × 4

= ^{3650 × 8 × 4}/₁₀₀

= ^{29200 × 4}/₁₀₀

= ¹¹⁶⁸⁰⁰/₁₀₀

= $1168

Thus, Simple Interest = $1168

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 = $3650 + $1168

= $4818

Thus, Amount to be paid = $4818 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 = $3650

Rate of Simple Interest (SI) or (R) = 8%

And, Time (t) = 4 years

Thus, Amount (A)

= $3650 + ($3650 × 8% × 4)

= $3650 + ($3650 ×⁸/₁₀₀ × 4)

= $3650 + (^{3650 × 8 × 4}/₁₀₀)

= $3650 + (^{29200 × 4}/₁₀₀)

= $3650 + (¹¹⁶⁸⁰⁰/₁₀₀)

= $3650 + $1168 = $4818

Thus, Amount (A) to be paid = $4818 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 $3650, the simple interest in 1 year

= ⁸/₁₀₀ × 3650

= ^{8 × 3650}/₁₀₀

= ²⁹²⁰⁰/₁₀₀ = $292

Thus, simple interest for 1 year = $292

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $292 × 4 = $1168

Thus, Simple Interest (SI) = $1168

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3650 + $1168

= $4818

Thus, Amount to be paid = $4818 Answer

Similar Questions

(1) Patricia took a loan of $4300 at the rate of 8% simple interest per annum. If he paid an amount of $7052 to clear the loan, then find the time period of the loan.

(2) Donald took a loan of $7000 at the rate of 10% simple interest per annum. If he paid an amount of $11200 to clear the loan, then find the time period of the loan.

(3) What amount does Linda have to pay after 5 years if he takes a loan of $3350 at 6% simple interest?

(4) If Charles borrowed $3900 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 years.

(5) Elizabeth took a loan of $4900 at the rate of 6% simple interest per annum. If he paid an amount of $7840 to clear the loan, then find the time period of the loan.

(6) John took a loan of $4400 at the rate of 8% simple interest per annum. If he paid an amount of $6512 to clear the loan, then find the time period of the loan.

(7) Patricia took a loan of $4300 at the rate of 10% simple interest per annum. If he paid an amount of $7740 to clear the loan, then find the time period of the loan.

(8) Find the amount to be paid if Patricia borrowed a sum of $5150 at 3% simple interest for 8 years.

(9) Calculate the amount due if Susan borrowed a sum of $3650 at 7% simple interest for 3 years.

(10) Patricia took a loan of $4300 at the rate of 9% simple interest per annum. If he paid an amount of $7783 to clear the loan, then find the time period of the loan.