Simple Interest
MCQs Math


Question:     What amount does Sarah have to pay after 6 years if he takes a loan of $3850 at 10% simple interest?


Correct Answer  $6160

Solution And Explanation

Solution

Given,

Principal (P) = $3850

Rate of Simple Interest (SI) = 10%

Time (t) = 6 years

Thus, Amount (A) = ?

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

Thus, here 10% simple interest means, Rate of Simple Interest (SI) is 10% 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 × 10% × 6

= $3850 ×10/100 × 6

= 3850 × 10 × 6/100

= 38500 × 6/100

= 231000/100

= $2310

Thus, Simple Interest = $2310

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 + $2310

= $6160

Thus, Amount to be paid = $6160 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) = 10%

And, Time (t) = 6 years

Thus, Amount (A)

= $3850 + ($3850 × 10% × 6)

= $3850 + ($3850 ×10/100 × 6)

= $3850 + (3850 × 10 × 6/100)

= $3850 + (38500 × 6/100)

= $3850 + (231000/100)

= $3850 + $2310 = $6160

Thus, Amount (A) to be paid = $6160 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 10%

This, means, $10 per $100 per year

∵ For $100, the simple interest for 1 year = $10

∴ For $1, the simple interest for 1 year = 10/100

∴ For $3850, the simple interest in 1 year

= 10/100 × 3850

= 10 × 3850/100

= 38500/100 = $385

Thus, simple interest for 1 year = $385

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $385 × 6 = $2310

Thus, Simple Interest (SI) = $2310

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3850 + $2310

= $6160

Thus, Amount to be paid = $6160 Answer


Similar Questions

(1) Mary took a loan of $4100 at the rate of 8% simple interest per annum. If he paid an amount of $6068 to clear the loan, then find the time period of the loan.

(2) Calculate the amount due if Richard borrowed a sum of $3600 at 6% simple interest for 4 years.

(3) Jessica had to pay $3975 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(4) If Linda borrowed $3350 from a bank at a rate of 2% simple interest per annum then find the amount to be paid after 2 years.

(5) If David paid $3944 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(6) Karen took a loan of $5900 at the rate of 9% simple interest per annum. If he paid an amount of $9086 to clear the loan, then find the time period of the loan.

(7) How much loan did Karen borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $6545 to clear it?

(8) How much loan did Thomas borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $6960 to clear it?

(9) Calculate the amount due if Jessica borrowed a sum of $3750 at 7% simple interest for 4 years.

(10) What amount does Michael have to pay after 6 years if he takes a loan of $3300 at 4% simple interest?


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