Simple Interest
MCQs Math


Question:     Linda took a loan of $4700 at the rate of 9% simple interest per annum. If he paid an amount of $8507 to clear the loan, then find the time period of the loan.


Correct Answer  9

Solution And Explanation

Solution

Given,

Principal (P) = $4700

Rate of Simple Interest (R) = 9% per annum

Amount (A) = $8507

Thus, time (T) = ?

Method (1) Using Formula

Calculation of Simple Interest, when Principal and Amount are given

Formual to Calculate Simple Interest when Principal and Amount are given

We know that, Amount (A) = Principal (P) + Simple Interest (SI)

⇒ Simple Interest (SI) = Amount – Principal

⇒ SI = $8507 – $4700 = $3807

Thus, Simple Interest = $3807

Calculation of the Time using forumula when Amount, Simple Interest and Principal are known

Formula to find the Time (T)

Time (T) = 100 × Simple Interest/Principal × Rate of Interest

⇒ T = 100 × SI/P × R

Thus, Time (T) = 100 × 3807/4700 × 9

= 380700/42300

= 9 years (using formula)

Thus, Time (T) = 9 years (from time taken before calculation)Answer

Calculation of the Time using Unitary Method when Amount, Simple Interest and Principal are known

Here, we have

Principal (P) = $4700

Rate of Simple Interest (R) = 9% per annum

Simple Interest = $3807 (As calculated above by subtracting Principal from the Amount given)

We know that, interest is calculated on the basis of the Principal.

This means Simple Interest for 1 year = Rate of simple interest × Principal

Thus, Simple Interest for 1 year = 9% of Principal

= 9% of $4700

= 9/100 × 4700

= 9 × 4700/100

= 42300/100 = 423

Thus, simple Interest for 1 year = $423

Now,

∵ If the simple Interest is $423, then the time = 1 year

∴ If the simple Interest is $1, then the time = 1/423 years

∴ If the simple Interest is $3807, then the time = 1/423 × 3807 years

= 1 × 3807/423 years

= 3807/423 = 9 years

Thus, time (T) = 9 years Answer


Similar Questions

(1) What amount will be due after 2 years if Paul borrowed a sum of $3850 at a 10% simple interest?

(2) Lisa had to pay $4657.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(3) Calculate the amount due if Mary borrowed a sum of $3050 at 3% simple interest for 3 years.

(4) Joseph had to pay $4255 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(5) Find the amount to be paid if Karen borrowed a sum of $5950 at 10% simple interest for 7 years.

(6) What amount does Patricia have to pay after 6 years if he takes a loan of $3150 at 9% simple interest?

(7) Calculate the amount due if Jessica borrowed a sum of $3750 at 4% simple interest for 4 years.

(8) If David paid $4080 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(9) In how much time a principal of $3050 will amount to $3660 at a simple interest of 5% per annum?

(10) What amount does John have to pay after 6 years if he takes a loan of $3200 at 2% simple interest?


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