Simple Interest
MCQs Math


Question:     What amount does Mary have to pay after 5 years if he takes a loan of $3050 at 10% simple interest?


Correct Answer  $4575

Solution And Explanation

Solution

Given,

Principal (P) = $3050

Rate of Simple Interest (SI) = 10%

Time (t) = 5 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) = $3050 × 10% × 5

= $3050 ×10/100 × 5

= 3050 × 10 × 5/100

= 30500 × 5/100

= 152500/100

= $1525

Thus, Simple Interest = $1525

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 = $3050 + $1525

= $4575

Thus, Amount to be paid = $4575 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 = $3050

Rate of Simple Interest (SI) or (R) = 10%

And, Time (t) = 5 years

Thus, Amount (A)

= $3050 + ($3050 × 10% × 5)

= $3050 + ($3050 ×10/100 × 5)

= $3050 + (3050 × 10 × 5/100)

= $3050 + (30500 × 5/100)

= $3050 + (152500/100)

= $3050 + $1525 = $4575

Thus, Amount (A) to be paid = $4575 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 $3050, the simple interest in 1 year

= 10/100 × 3050

= 10 × 3050/100

= 30500/100 = $305

Thus, simple interest for 1 year = $305

Therefore, simple interest for 5 years

= Simple interest for 1 year × 5

= $305 × 5 = $1525

Thus, Simple Interest (SI) = $1525

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3050 + $1525

= $4575

Thus, Amount to be paid = $4575 Answer


Similar Questions

(1) Anthony took a loan of $6600 at the rate of 8% simple interest per annum. If he paid an amount of $10824 to clear the loan, then find the time period of the loan.

(2) Calculate the amount due after 10 years if Michael borrowed a sum of $5300 at a rate of 8% simple interest.

(3) Find the amount to be paid if James borrowed a sum of $5000 at 5% simple interest for 7 years.

(4) If Richard paid $4176 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(5) Mary took a loan of $4100 at the rate of 7% simple interest per annum. If he paid an amount of $6970 to clear the loan, then find the time period of the loan.

(6) If Donald paid $5040 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(7) Find the amount to be paid if Charles borrowed a sum of $5900 at 4% simple interest for 8 years.

(8) Calculate the amount due after 9 years if William borrowed a sum of $5500 at a rate of 8% simple interest.

(9) Betty took a loan of $6500 at the rate of 6% simple interest per annum. If he paid an amount of $8840 to clear the loan, then find the time period of the loan.

(10) Thomas took a loan of $5600 at the rate of 6% simple interest per annum. If he paid an amount of $7952 to clear the loan, then find the time period of the loan.


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