Simple Interest
MCQs Math


Question:     Calculate the amount due if James borrowed a sum of $3000 at 7% simple interest for 3 years.


Correct Answer  $3630

Solution And Explanation

Solution

Given,

Principal (P) = $3000

Rate of Simple Interest (SI) = 7%

Time (t) = 3 years

Thus, Amount (A) = ?

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

Thus, here 7% simple interest means, Rate of Simple Interest (SI) is 7% 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) = $3000 × 7% × 3

= $3000 ×7/100 × 3

= 3000 × 7 × 3/100

= 21000 × 3/100

= 63000/100

= $630

Thus, Simple Interest = $630

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 = $3000 + $630

= $3630

Thus, Amount to be paid = $3630 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 = $3000

Rate of Simple Interest (SI) or (R) = 7%

And, Time (t) = 3 years

Thus, Amount (A)

= $3000 + ($3000 × 7% × 3)

= $3000 + ($3000 ×7/100 × 3)

= $3000 + (3000 × 7 × 3/100)

= $3000 + (21000 × 3/100)

= $3000 + (63000/100)

= $3000 + $630 = $3630

Thus, Amount (A) to be paid = $3630 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 7%

This, means, $7 per $100 per year

∵ For $100, the simple interest for 1 year = $7

∴ For $1, the simple interest for 1 year = 7/100

∴ For $3000, the simple interest in 1 year

= 7/100 × 3000

= 7 × 3000/100

= 21000/100 = $210

Thus, simple interest for 1 year = $210

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $210 × 3 = $630

Thus, Simple Interest (SI) = $630

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3000 + $630

= $3630

Thus, Amount to be paid = $3630 Answer


Similar Questions

(1) Margaret took a loan of $6700 at the rate of 7% simple interest per annum. If he paid an amount of $11390 to clear the loan, then find the time period of the loan.

(2) Calculate the amount due if Linda borrowed a sum of $3350 at 4% simple interest for 4 years.

(3) Patricia took a loan of $4300 at the rate of 10% simple interest per annum. If he paid an amount of $8600 to clear the loan, then find the time period of the loan.

(4) Calculate the amount due after 10 years if Karen borrowed a sum of $5950 at a rate of 4% simple interest.

(5) Margaret took a loan of $6700 at the rate of 10% simple interest per annum. If he paid an amount of $11390 to clear the loan, then find the time period of the loan.

(6) Lisa took a loan of $6100 at the rate of 10% simple interest per annum. If he paid an amount of $11590 to clear the loan, then find the time period of the loan.

(7) Donald took a loan of $7000 at the rate of 10% simple interest per annum. If he paid an amount of $11900 to clear the loan, then find the time period of the loan.

(8) Calculate the amount due after 9 years if Richard borrowed a sum of $5600 at a rate of 10% simple interest.

(9) How much loan did David borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $6210 to clear it?

(10) John took a loan of $4400 at the rate of 6% simple interest per annum. If he paid an amount of $7040 to clear the loan, then find the time period of the loan.


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