Simple Interest
MCQs Math


Question:     What amount does Sarah have to pay after 6 years if he takes a loan of $3850 at 8% simple interest?


Correct Answer  $5698

Solution And Explanation

Solution

Given,

Principal (P) = $3850

Rate of Simple Interest (SI) = 8%

Time (t) = 6 years

Thus, Amount (A) = ?

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

Thus, here 8% simple interest means, Rate of Simple Interest (SI) is 8% 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 × 8% × 6

= $3850 ×8/100 × 6

= 3850 × 8 × 6/100

= 30800 × 6/100

= 184800/100

= $1848

Thus, Simple Interest = $1848

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 + $1848

= $5698

Thus, Amount to be paid = $5698 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) = 8%

And, Time (t) = 6 years

Thus, Amount (A)

= $3850 + ($3850 × 8% × 6)

= $3850 + ($3850 ×8/100 × 6)

= $3850 + (3850 × 8 × 6/100)

= $3850 + (30800 × 6/100)

= $3850 + (184800/100)

= $3850 + $1848 = $5698

Thus, Amount (A) to be paid = $5698 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 8%

This, means, $8 per $100 per year

∵ For $100, the simple interest for 1 year = $8

∴ For $1, the simple interest for 1 year = 8/100

∴ For $3850, the simple interest in 1 year

= 8/100 × 3850

= 8 × 3850/100

= 30800/100 = $308

Thus, simple interest for 1 year = $308

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $308 × 6 = $1848

Thus, Simple Interest (SI) = $1848

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3850 + $1848

= $5698

Thus, Amount to be paid = $5698 Answer


Similar Questions

(1) Calculate the amount due after 9 years if Susan borrowed a sum of $5650 at a rate of 6% simple interest.

(2) What amount will be due after 2 years if William borrowed a sum of $3250 at a 8% simple interest?

(3) How much loan did Robert borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $6375 to clear it?

(4) How much loan did Timothy borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $8140 to clear it?

(5) If Mark paid $5104 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(6) Michael had to pay $3696 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(7) Joseph took a loan of $5400 at the rate of 6% simple interest per annum. If he paid an amount of $7344 to clear the loan, then find the time period of the loan.

(8) Calculate the amount due after 10 years if Robert borrowed a sum of $5100 at a rate of 3% simple interest.

(9) If Lisa paid $4536 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(10) Jessica took a loan of $5500 at the rate of 6% simple interest per annum. If he paid an amount of $7810 to clear the loan, then find the time period of the loan.


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