Simple Interest
MCQs Math


Question:     What amount does Barbara have to pay after 6 years if he takes a loan of $3550 at 3% simple interest?


Correct Answer  $4189

Solution And Explanation

Solution

Given,

Principal (P) = $3550

Rate of Simple Interest (SI) = 3%

Time (t) = 6 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) = $3550 × 3% × 6

= $3550 ×3/100 × 6

= 3550 × 3 × 6/100

= 10650 × 6/100

= 63900/100

= $639

Thus, Simple Interest = $639

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 + $639

= $4189

Thus, Amount to be paid = $4189 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) = 3%

And, Time (t) = 6 years

Thus, Amount (A)

= $3550 + ($3550 × 3% × 6)

= $3550 + ($3550 ×3/100 × 6)

= $3550 + (3550 × 3 × 6/100)

= $3550 + (10650 × 6/100)

= $3550 + (63900/100)

= $3550 + $639 = $4189

Thus, Amount (A) to be paid = $4189 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 $3550, the simple interest in 1 year

= 3/100 × 3550

= 3 × 3550/100

= 10650/100 = $106.5

Thus, simple interest for 1 year = $106.5

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $106.5 × 6 = $639

Thus, Simple Interest (SI) = $639

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3550 + $639

= $4189

Thus, Amount to be paid = $4189 Answer


Similar Questions

(1) Calculate the amount due if Susan borrowed a sum of $3650 at 5% simple interest for 3 years.

(2) Sandra took a loan of $6900 at the rate of 6% simple interest per annum. If he paid an amount of $10212 to clear the loan, then find the time period of the loan.

(3) Daniel took a loan of $6200 at the rate of 9% simple interest per annum. If he paid an amount of $10664 to clear the loan, then find the time period of the loan.

(4) Donna had to pay $5577.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(5) Mary took a loan of $4100 at the rate of 8% simple interest per annum. If he paid an amount of $7380 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due if Barbara borrowed a sum of $3550 at 6% simple interest for 3 years.

(7) Find the amount to be paid if John borrowed a sum of $5200 at 3% simple interest for 8 years.

(8) Calculate the amount due if Sarah borrowed a sum of $3850 at 9% simple interest for 4 years.

(9) How much loan did Mary borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $6312.5 to clear it?

(10) Anthony took a loan of $6600 at the rate of 8% simple interest per annum. If he paid an amount of $11352 to clear the loan, then find the time period of the loan.


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