Simple Interest
MCQs Math


Question:     What amount does Elizabeth have to pay after 6 years if he takes a loan of $3450 at 8% simple interest?


Correct Answer  $5106

Solution And Explanation

Solution

Given,

Principal (P) = $3450

Rate of Simple Interest (SI) = 8%

Time (t) = 6 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) = $3450 × 8% × 6

= $3450 ×8/100 × 6

= 3450 × 8 × 6/100

= 27600 × 6/100

= 165600/100

= $1656

Thus, Simple Interest = $1656

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 = $3450 + $1656

= $5106

Thus, Amount to be paid = $5106 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 = $3450

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

And, Time (t) = 6 years

Thus, Amount (A)

= $3450 + ($3450 × 8% × 6)

= $3450 + ($3450 ×8/100 × 6)

= $3450 + (3450 × 8 × 6/100)

= $3450 + (27600 × 6/100)

= $3450 + (165600/100)

= $3450 + $1656 = $5106

Thus, Amount (A) to be paid = $5106 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 $3450, the simple interest in 1 year

= 8/100 × 3450

= 8 × 3450/100

= 27600/100 = $276

Thus, simple interest for 1 year = $276

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $276 × 6 = $1656

Thus, Simple Interest (SI) = $1656

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3450 + $1656

= $5106

Thus, Amount to be paid = $5106 Answer


Similar Questions

(1) In how much time a principal of $3200 will amount to $4000 at a simple interest of 5% per annum?

(2) Find the amount to be paid if Sarah borrowed a sum of $5850 at 9% simple interest for 7 years.

(3) Find the amount to be paid if Thomas borrowed a sum of $5800 at 6% simple interest for 8 years.

(4) Matthew had to pay $4452 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(5) What amount will be due after 2 years if Mark borrowed a sum of $3700 at a 9% simple interest?

(6) In how much time a principal of $3050 will amount to $3294 at a simple interest of 2% per annum?

(7) Sandra took a loan of $6900 at the rate of 9% simple interest per annum. If he paid an amount of $12489 to clear the loan, then find the time period of the loan.

(8) Robert took a loan of $4200 at the rate of 9% simple interest per annum. If he paid an amount of $7980 to clear the loan, then find the time period of the loan.

(9) Barbara took a loan of $5100 at the rate of 9% simple interest per annum. If he paid an amount of $8772 to clear the loan, then find the time period of the loan.

(10) What amount will be due after 2 years if John borrowed a sum of $3100 at a 7% simple interest?


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