Question

At what percent per annum simple interest will Rs.66000 amount to Rs 72720 in 2 years

Answer 1

Hint: We have the formula of Simple interest as \[SI=\dfrac{PRT}{100}\], where P is the Principal, R is the Rate of interest and T is the time in years. We will use this formula to solve the given question.

Complete step-by-step answer:
 The values given are Principal P= 66000, Amount A=72720, and Time T=2 years.
Observing the question, we are given the principle, P and amount, A so we can easily calculate the Simple interest SI using the formula,
SI = A – P
Therefore, the value of SI will be
SI = 72720-66000 = Rs.6720
Now, since after obtaining the value of Simple Interest i.e., SI as Rs 6720 we can easily find out the rate of interest which is to be determined , by using the formula,
\[SI=\dfrac{PRT}{100}\]
Rearranging of the above formula gives the rate of interest as,
\[R=\dfrac{\left( SI \right)\left( 100 \right)}{PT}\]
Substituting the values given we get,
  $ R=\dfrac{\left( 6720 \right)\left( 100 \right)}{\left( 66000 \right)\left( 2 \right)} \\ $
 $ R=\dfrac{672000}{132000} \\ $
 $ R=5.09\% \\
$
Hence, we obtain the Rate of interest as 5.09%, which is the required answer of the question.
Note: While solving the question one should take care that he does not mix the values of Principle, Amount and simple interest as they are three different identities. While solving the question take out the values of most of the things using the information given in the question itself.