Simple Interest
MCQs Math


Question:     Find the amount to be paid if Christopher borrowed a sum of $6000 at 7% simple interest for 8 years.


Correct Answer  $9360

Solution And Explanation

Solution

Given,

Principal (P) = $6000

Rate of Simple Interest (SI) = 7%

Time (t) = 8 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) = $6000 × 7% × 8

= $6000 ×7/100 × 8

= 6000 × 7 × 8/100

= 42000 × 8/100

= 336000/100

= $3360

Thus, Simple Interest = $3360

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 = $6000 + $3360

= $9360

Thus, Amount to be paid = $9360 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 = $6000

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

And, Time (t) = 8 years

Thus, Amount (A)

= $6000 + ($6000 × 7% × 8)

= $6000 + ($6000 ×7/100 × 8)

= $6000 + (6000 × 7 × 8/100)

= $6000 + (42000 × 8/100)

= $6000 + (336000/100)

= $6000 + $3360 = $9360

Thus, Amount (A) to be paid = $9360 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 $6000, the simple interest in 1 year

= 7/100 × 6000

= 7 × 6000/100

= 42000/100 = $420

Thus, simple interest for 1 year = $420

Therefore, simple interest for 8 years

= Simple interest for 1 year × 8

= $420 × 8 = $3360

Thus, Simple Interest (SI) = $3360

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $6000 + $3360

= $9360

Thus, Amount to be paid = $9360 Answer


Similar Questions

(1) What amount does Jennifer have to pay after 5 years if he takes a loan of $3250 at 6% simple interest?

(2) Patricia took a loan of $4300 at the rate of 7% simple interest per annum. If he paid an amount of $6407 to clear the loan, then find the time period of the loan.

(3) Calculate the amount due after 10 years if Susan borrowed a sum of $5650 at a rate of 6% simple interest.

(4) Calculate the amount due after 10 years if Jennifer borrowed a sum of $5250 at a rate of 7% simple interest.

(5) Find the amount to be paid if Charles borrowed a sum of $5900 at 2% simple interest for 8 years.

(6) Jessica took a loan of $5500 at the rate of 8% simple interest per annum. If he paid an amount of $8580 to clear the loan, then find the time period of the loan.

(7) William took a loan of $5000 at the rate of 8% simple interest per annum. If he paid an amount of $8600 to clear the loan, then find the time period of the loan.

(8) Jennifer took a loan of $4500 at the rate of 9% simple interest per annum. If he paid an amount of $6930 to clear the loan, then find the time period of the loan.

(9) Calculate the amount due after 10 years if Richard borrowed a sum of $5600 at a rate of 2% simple interest.

(10) If Linda paid $3886 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.


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