Simple Interest
MCQs Math


Question:     What amount does Elizabeth have to pay after 5 years if he takes a loan of $3450 at 6% simple interest?


Correct Answer  $4485

Solution And Explanation

Solution

Given,

Principal (P) = $3450

Rate of Simple Interest (SI) = 6%

Time (t) = 5 years

Thus, Amount (A) = ?

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

Thus, here 6% simple interest means, Rate of Simple Interest (SI) is 6% 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) = $3450 × 6% × 5

= $3450 ×6/100 × 5

= 3450 × 6 × 5/100

= 20700 × 5/100

= 103500/100

= $1035

Thus, Simple Interest = $1035

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 = $3450 + $1035

= $4485

Thus, Amount to be paid = $4485 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 = $3450

Rate of Simple Interest (SI) or (R) = 6%

And, Time (t) = 5 years

Thus, Amount (A)

= $3450 + ($3450 × 6% × 5)

= $3450 + ($3450 ×6/100 × 5)

= $3450 + (3450 × 6 × 5/100)

= $3450 + (20700 × 5/100)

= $3450 + (103500/100)

= $3450 + $1035 = $4485

Thus, Amount (A) to be paid = $4485 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 6%

This, means, $6 per $100 per year

∵ For $100, the simple interest for 1 year = $6

∴ For $1, the simple interest for 1 year = 6/100

∴ For $3450, the simple interest in 1 year

= 6/100 × 3450

= 6 × 3450/100

= 20700/100 = $207

Thus, simple interest for 1 year = $207

Therefore, simple interest for 5 years

= Simple interest for 1 year × 5

= $207 × 5 = $1035

Thus, Simple Interest (SI) = $1035

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3450 + $1035

= $4485

Thus, Amount to be paid = $4485 Answer


Similar Questions

(1) If Kenneth paid $5400 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(2) Daniel took a loan of $6200 at the rate of 6% simple interest per annum. If he paid an amount of $8804 to clear the loan, then find the time period of the loan.

(3) Sandra took a loan of $6900 at the rate of 9% simple interest per annum. If he paid an amount of $11868 to clear the loan, then find the time period of the loan.

(4) Calculate the amount due after 9 years if Robert borrowed a sum of $5100 at a rate of 6% simple interest.

(5) James had to pay $3180 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(6) Thomas had to pay $4256 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(7) Donald took a loan of $7000 at the rate of 8% simple interest per annum. If he paid an amount of $11480 to clear the loan, then find the time period of the loan.

(8) Thomas took a loan of $5600 at the rate of 10% simple interest per annum. If he paid an amount of $10640 to clear the loan, then find the time period of the loan.

(9) Lisa took a loan of $6100 at the rate of 6% simple interest per annum. If he paid an amount of $9760 to clear the loan, then find the time period of the loan.

(10) What amount does Mary have to pay after 6 years if he takes a loan of $3050 at 8% simple interest?


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