Simple Interest
MCQs Math


Question:     Joseph took a loan of $5400 at the rate of 7% simple interest per annum. If he paid an amount of $8424 to clear the loan, then find the time period of the loan.


Correct Answer  8

Solution And Explanation

Solution

Given,

Principal (P) = $5400

Rate of Simple Interest (R) = 7% per annum

Amount (A) = $8424

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 = $8424 – $5400 = $3024

Thus, Simple Interest = $3024

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 × 3024/5400 × 7

= 302400/37800

= 8 years (using formula)

Thus, Time (T) = 8 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) = $5400

Rate of Simple Interest (R) = 7% per annum

Simple Interest = $3024 (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 = 7% of Principal

= 7% of $5400

= 7/100 × 5400

= 7 × 5400/100

= 37800/100 = 378

Thus, simple Interest for 1 year = $378

Now,

∵ If the simple Interest is $378, then the time = 1 year

∴ If the simple Interest is $1, then the time = 1/378 years

∴ If the simple Interest is $3024, then the time = 1/378 × 3024 years

= 1 × 3024/378 years

= 3024/378 = 8 years

Thus, time (T) = 8 years Answer


Similar Questions

(1) What amount does Charles have to pay after 6 years if he takes a loan of $3900 at 7% simple interest?

(2) Calculate the amount due if Karen borrowed a sum of $3950 at 3% simple interest for 3 years.

(3) What amount does Jessica have to pay after 6 years if he takes a loan of $3750 at 3% simple interest?

(4) If Lisa paid $4698 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(5) In how much time a principal of $3100 will amount to $3472 at a simple interest of 4% per annum?

(6) Calculate the amount due after 10 years if Patricia borrowed a sum of $5150 at a rate of 10% simple interest.

(7) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 10% simple interest for 8 years.

(8) If Mark paid $5280 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(9) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 3% simple interest for 8 years.

(10) Calculate the amount due after 9 years if Mary borrowed a sum of $5050 at a rate of 5% simple interest.


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