Simple Interest
MCQs Math


Question:     Calculate the amount due if Sarah borrowed a sum of $3850 at 3% simple interest for 4 years.


Correct Answer  $4312

Solution And Explanation

Solution

Given,

Principal (P) = $3850

Rate of Simple Interest (SI) = 3%

Time (t) = 4 years

Thus, Amount (A) = ?

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

Thus, here 3% simple interest means, Rate of Simple Interest (SI) is 3% 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) = $3850 × 3% × 4

= $3850 ×3/100 × 4

= 3850 × 3 × 4/100

= 11550 × 4/100

= 46200/100

= $462

Thus, Simple Interest = $462

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 = $3850 + $462

= $4312

Thus, Amount to be paid = $4312 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 = $3850

Rate of Simple Interest (SI) or (R) = 3%

And, Time (t) = 4 years

Thus, Amount (A)

= $3850 + ($3850 × 3% × 4)

= $3850 + ($3850 ×3/100 × 4)

= $3850 + (3850 × 3 × 4/100)

= $3850 + (11550 × 4/100)

= $3850 + (46200/100)

= $3850 + $462 = $4312

Thus, Amount (A) to be paid = $4312 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 3%

This, means, $3 per $100 per year

∵ For $100, the simple interest for 1 year = $3

∴ For $1, the simple interest for 1 year = 3/100

∴ For $3850, the simple interest in 1 year

= 3/100 × 3850

= 3 × 3850/100

= 11550/100 = $115.5

Thus, simple interest for 1 year = $115.5

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $115.5 × 4 = $462

Thus, Simple Interest (SI) = $462

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3850 + $462

= $4312

Thus, Amount to be paid = $4312 Answer


Similar Questions

(1) Lisa took a loan of $6100 at the rate of 7% simple interest per annum. If he paid an amount of $9516 to clear the loan, then find the time period of the loan.

(2) Anthony had to pay $4816 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(3) Find the amount to be paid if David borrowed a sum of $5400 at 2% simple interest for 8 years.

(4) How much loan did Karen borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $7140 to clear it?

(5) Calculate the amount due after 9 years if David borrowed a sum of $5400 at a rate of 2% simple interest.

(6) Calculate the amount due after 9 years if David borrowed a sum of $5400 at a rate of 6% simple interest.

(7) In how much time a principal of $3000 will amount to $3450 at a simple interest of 3% per annum?

(8) Karen had to pay $4187 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(9) If David paid $4080 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(10) Find the amount to be paid if Susan borrowed a sum of $5650 at 9% simple interest for 8 years.


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