Simple Interest
MCQs Math


Question:     What amount does Robert have to pay after 6 years if he takes a loan of $3100 at 3% simple interest?


Correct Answer  $3658

Solution And Explanation

Solution

Given,

Principal (P) = $3100

Rate of Simple Interest (SI) = 3%

Time (t) = 6 years

Thus, Amount (A) = ?

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

Thus, here 3% simple interest means, Rate of Simple Interest (SI) is 3% 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) = $3100 × 3% × 6

= $3100 ×3/100 × 6

= 3100 × 3 × 6/100

= 9300 × 6/100

= 55800/100

= $558

Thus, Simple Interest = $558

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 = $3100 + $558

= $3658

Thus, Amount to be paid = $3658 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 = $3100

Rate of Simple Interest (SI) or (R) = 3%

And, Time (t) = 6 years

Thus, Amount (A)

= $3100 + ($3100 × 3% × 6)

= $3100 + ($3100 ×3/100 × 6)

= $3100 + (3100 × 3 × 6/100)

= $3100 + (9300 × 6/100)

= $3100 + (55800/100)

= $3100 + $558 = $3658

Thus, Amount (A) to be paid = $3658 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 3%

This, means, $3 per $100 per year

∵ For $100, the simple interest for 1 year = $3

∴ For $1, the simple interest for 1 year = 3/100

∴ For $3100, the simple interest in 1 year

= 3/100 × 3100

= 3 × 3100/100

= 9300/100 = $93

Thus, simple interest for 1 year = $93

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $93 × 6 = $558

Thus, Simple Interest (SI) = $558

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3100 + $558

= $3658

Thus, Amount to be paid = $3658 Answer


Similar Questions

(1) What amount does Jessica have to pay after 5 years if he takes a loan of $3750 at 6% simple interest?

(2) If Paul paid $5640 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(3) In how much time a principal of $3100 will amount to $3348 at a simple interest of 2% per annum?

(4) Donald took a loan of $7000 at the rate of 6% simple interest per annum. If he paid an amount of $9940 to clear the loan, then find the time period of the loan.

(5) What amount does Jessica have to pay after 5 years if he takes a loan of $3750 at 4% simple interest?

(6) Jessica took a loan of $5500 at the rate of 7% simple interest per annum. If he paid an amount of $8195 to clear the loan, then find the time period of the loan.

(7) Nancy took a loan of $6300 at the rate of 7% simple interest per annum. If he paid an amount of $8946 to clear the loan, then find the time period of the loan.

(8) Joseph took a loan of $5400 at the rate of 8% simple interest per annum. If he paid an amount of $8424 to clear the loan, then find the time period of the loan.

(9) James took a loan of $4000 at the rate of 8% simple interest per annum. If he paid an amount of $6880 to clear the loan, then find the time period of the loan.

(10) What amount will be due after 2 years if Andrew borrowed a sum of $3900 at a 8% simple interest?


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