Simple Interest
MCQs Math


Question:     What amount does Barbara have to pay after 6 years if he takes a loan of $3550 at 6% simple interest?


Correct Answer  $4828

Solution And Explanation

Solution

Given,

Principal (P) = $3550

Rate of Simple Interest (SI) = 6%

Time (t) = 6 years

Thus, Amount (A) = ?

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

Thus, here 6% simple interest means, Rate of Simple Interest (SI) is 6% 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 × 6% × 6

= $3550 ×6/100 × 6

= 3550 × 6 × 6/100

= 21300 × 6/100

= 127800/100

= $1278

Thus, Simple Interest = $1278

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 + $1278

= $4828

Thus, Amount to be paid = $4828 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) = 6%

And, Time (t) = 6 years

Thus, Amount (A)

= $3550 + ($3550 × 6% × 6)

= $3550 + ($3550 ×6/100 × 6)

= $3550 + (3550 × 6 × 6/100)

= $3550 + (21300 × 6/100)

= $3550 + (127800/100)

= $3550 + $1278 = $4828

Thus, Amount (A) to be paid = $4828 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 6%

This, means, $6 per $100 per year

∵ For $100, the simple interest for 1 year = $6

∴ For $1, the simple interest for 1 year = 6/100

∴ For $3550, the simple interest in 1 year

= 6/100 × 3550

= 6 × 3550/100

= 21300/100 = $213

Thus, simple interest for 1 year = $213

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $213 × 6 = $1278

Thus, Simple Interest (SI) = $1278

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3550 + $1278

= $4828

Thus, Amount to be paid = $4828 Answer


Similar Questions

(1) In how much time a principal of $3150 will amount to $3465 at a simple interest of 5% per annum?

(2) Sarah took a loan of $5700 at the rate of 9% simple interest per annum. If he paid an amount of $9291 to clear the loan, then find the time period of the loan.

(3) How much loan did Deborah borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $8195 to clear it?

(4) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 4% simple interest for 7 years.

(5) Calculate the amount due if James borrowed a sum of $3000 at 7% simple interest for 4 years.

(6) Susan took a loan of $5300 at the rate of 8% simple interest per annum. If he paid an amount of $9116 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 $6880 to clear the loan, then find the time period of the loan.

(8) Find the amount to be paid if William borrowed a sum of $5500 at 5% simple interest for 7 years.

(9) Michael took a loan of $4600 at the rate of 9% simple interest per annum. If he paid an amount of $8326 to clear the loan, then find the time period of the loan.

(10) Michael took a loan of $4600 at the rate of 8% simple interest per annum. If he paid an amount of $6808 to clear the loan, then find the time period of the loan.


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