Simple Interest
MCQs Math


Question:     What amount does Barbara have to pay after 5 years if he takes a loan of $3550 at 8% simple interest?


Correct Answer  $4970

Solution And Explanation

Solution

Given,

Principal (P) = $3550

Rate of Simple Interest (SI) = 8%

Time (t) = 5 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) = $3550 × 8% × 5

= $3550 ×8/100 × 5

= 3550 × 8 × 5/100

= 28400 × 5/100

= 142000/100

= $1420

Thus, Simple Interest = $1420

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 = $3550 + $1420

= $4970

Thus, Amount to be paid = $4970 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 = $3550

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

And, Time (t) = 5 years

Thus, Amount (A)

= $3550 + ($3550 × 8% × 5)

= $3550 + ($3550 ×8/100 × 5)

= $3550 + (3550 × 8 × 5/100)

= $3550 + (28400 × 5/100)

= $3550 + (142000/100)

= $3550 + $1420 = $4970

Thus, Amount (A) to be paid = $4970 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 $3550, the simple interest in 1 year

= 8/100 × 3550

= 8 × 3550/100

= 28400/100 = $284

Thus, simple interest for 1 year = $284

Therefore, simple interest for 5 years

= Simple interest for 1 year × 5

= $284 × 5 = $1420

Thus, Simple Interest (SI) = $1420

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3550 + $1420

= $4970

Thus, Amount to be paid = $4970 Answer


Similar Questions

(1) What amount does Susan have to pay after 5 years if he takes a loan of $3650 at 5% simple interest?

(2) Linda took a loan of $4700 at the rate of 9% simple interest per annum. If he paid an amount of $7661 to clear the loan, then find the time period of the loan.

(3) William took a loan of $5000 at the rate of 8% simple interest per annum. If he paid an amount of $7800 to clear the loan, then find the time period of the loan.

(4) Karen took a loan of $5900 at the rate of 7% simple interest per annum. If he paid an amount of $8791 to clear the loan, then find the time period of the loan.

(5) Calculate the amount due after 9 years if Linda borrowed a sum of $5350 at a rate of 9% simple interest.

(6) Find the amount to be paid if Charles borrowed a sum of $5900 at 8% simple interest for 7 years.

(7) Joseph had to pay $3922 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(8) David took a loan of $4800 at the rate of 6% simple interest per annum. If he paid an amount of $7680 to clear the loan, then find the time period of the loan.

(9) Find the amount to be paid if Mary borrowed a sum of $5050 at 8% simple interest for 7 years.

(10) Karen took a loan of $5900 at the rate of 10% simple interest per annum. If he paid an amount of $11210 to clear the loan, then find the time period of the loan.


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