Simple Interest
MCQs Math


Question:     What amount does Karen have to pay after 5 years if he takes a loan of $3950 at 10% simple interest?


Correct Answer  $5925

Solution And Explanation

Solution

Given,

Principal (P) = $3950

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) = $3950 × 10% × 5

= $3950 ×10/100 × 5

= 3950 × 10 × 5/100

= 39500 × 5/100

= 197500/100

= $1975

Thus, Simple Interest = $1975

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 = $3950 + $1975

= $5925

Thus, Amount to be paid = $5925 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 = $3950

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

And, Time (t) = 5 years

Thus, Amount (A)

= $3950 + ($3950 × 10% × 5)

= $3950 + ($3950 ×10/100 × 5)

= $3950 + (3950 × 10 × 5/100)

= $3950 + (39500 × 5/100)

= $3950 + (197500/100)

= $3950 + $1975 = $5925

Thus, Amount (A) to be paid = $5925 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 $3950, the simple interest in 1 year

= 10/100 × 3950

= 10 × 3950/100

= 39500/100 = $395

Thus, simple interest for 1 year = $395

Therefore, simple interest for 5 years

= Simple interest for 1 year × 5

= $395 × 5 = $1975

Thus, Simple Interest (SI) = $1975

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3950 + $1975

= $5925

Thus, Amount to be paid = $5925 Answer


Similar Questions

(1) Michael took a loan of $4600 at the rate of 6% simple interest per annum. If he paid an amount of $7084 to clear the loan, then find the time period of the loan.

(2) What amount will be due after 2 years if Joseph borrowed a sum of $3350 at a 6% simple interest?

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

(4) What amount will be due after 2 years if Charles borrowed a sum of $3450 at a 6% simple interest?

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

(6) Calculate the amount due after 9 years if Jennifer borrowed a sum of $5250 at a rate of 6% simple interest.

(7) Calculate the amount due if Elizabeth borrowed a sum of $3450 at 10% simple interest for 4 years.

(8) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 4% simple interest for 8 years.

(9) What amount will be due after 2 years if Anthony borrowed a sum of $3650 at a 7% simple interest?

(10) Find the amount to be paid if Sarah borrowed a sum of $5850 at 2% simple interest for 7 years.


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