Simple Interest
MCQs Math


Question:     What amount does Karen have to pay after 5 years if he takes a loan of $3950 at 10% simple interest?


Correct Answer  $5925

Solution And Explanation

Solution

Given,

Principal (P) = $3950

Rate of Simple Interest (SI) = 10%

Time (t) = 5 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) = $3950 × 10% × 5

= $3950 ×10/100 × 5

= 3950 × 10 × 5/100

= 39500 × 5/100

= 197500/100

= $1975

Thus, Simple Interest = $1975

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 = $3950 + $1975

= $5925

Thus, Amount to be paid = $5925 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 = $3950

Rate of Simple Interest (SI) or (R) = 10%

And, Time (t) = 5 years

Thus, Amount (A)

= $3950 + ($3950 × 10% × 5)

= $3950 + ($3950 ×10/100 × 5)

= $3950 + (3950 × 10 × 5/100)

= $3950 + (39500 × 5/100)

= $3950 + (197500/100)

= $3950 + $1975 = $5925

Thus, Amount (A) to be paid = $5925 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 $3950, the simple interest in 1 year

= 10/100 × 3950

= 10 × 3950/100

= 39500/100 = $395

Thus, simple interest for 1 year = $395

Therefore, simple interest for 5 years

= Simple interest for 1 year × 5

= $395 × 5 = $1975

Thus, Simple Interest (SI) = $1975

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3950 + $1975

= $5925

Thus, Amount to be paid = $5925 Answer


Similar Questions

(1) Donna had to pay $5577.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(2) If Michelle paid $5940 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(3) How much loan did Kevin borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $8520 to clear it?

(4) How much loan did Karen borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $6842.5 to clear it?

(5) What amount will be due after 2 years if Mark borrowed a sum of $3700 at a 6% simple interest?

(6) Michael took a loan of $4600 at the rate of 8% simple interest per annum. If he paid an amount of $7176 to clear the loan, then find the time period of the loan.

(7) Joseph took a loan of $5400 at the rate of 6% simple interest per annum. If he paid an amount of $7992 to clear the loan, then find the time period of the loan.

(8) Susan took a loan of $5300 at the rate of 6% simple interest per annum. If he paid an amount of $8162 to clear the loan, then find the time period of the loan.

(9) Find the amount to be paid if Karen borrowed a sum of $5950 at 5% simple interest for 8 years.

(10) Matthew had to pay $4578 in order to furnish the loan taken 3 years before. If the rate of simple interest was 3% then find the sum borrowed.


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