Find the S.I for Rs. $ 850 $ from 10th March to 3rd August at $ 2\dfrac{1}{2}\% $ p.a.

Hint: Simple interest is a quick and easy method of calculating the interest charged on a loan. Simple interest is determined by multiplying the daily interest rate by the principal and the number of days that elapse between payments. We use the formula of simple interest as $ S.I = \dfrac{{P \times R \times T}}{{100}} $
Where, P $ = $ Principal
R $ = $ Rate of interest
T $ = $ Time

Complete step-by-step answer:
Here, $ P = $ ₹ $ 850 $
 $ R = 2\dfrac{1}{2}\% = \dfrac{5}{2}\% $
 $ T = {10^{th}} $ march to 3rd august
Now we calculate time by month wise.
We will convert days in years. From 10th march to 3rd august it becomes $ 146 $,converting it into years
 $ \Rightarrow T = \dfrac{{146}}{{365}} $ years
By dividing $ \dfrac{{146}}{{365}} $ by $ 73 $ in numerator and denominator, we will get
 $ \Rightarrow T = \dfrac{2}{5} $ years
Now, we will use the simple interest formula
\[\Rightarrow S.I = \dfrac{{P \times R \times T}}{{100}}\]
 $ \Rightarrow S.I = \dfrac{{850 \times \dfrac{5}{2} \times \dfrac{2}{5}}}{{100}} $
 $ \Rightarrow S.I = \dfrac{{850 \times 5 \times 2}}{{100 \times 2 \times 5}} $
 $ \Rightarrow S.I = \dfrac{{85}}{{10}} $
 $ \Rightarrow S.I = 8.50 $
 $ \Rightarrow S.I = 8.50 $
Therefore, $ S.I = $ ₹ $ 8.50 $

Note: Students should read the question carefully as sometimes in the question the time period is given in years or in months or in days. So, one must solve the question as per the given data in the question and convert the time unit in terms of years.