It has been seen in a survey of a region that $70$ persons read English newspaper, $73$ persons read Bengali newspaper and $64$ persons read both the papers. If $63$ persons do not read any paper, on how many people has the survey been done?

Let $E$ be the set of individuals who read the English newspaper and $B$ be the set of individuals who read the Bengali newspaper.
We are given:

* Total reading English, $n(E)=70$
* Total reading Bengali, $n(B)=73$
* Total reading both papers, $n(E\cap B)=64$

Using the set theory principle of inclusion-exclusion, the total number of people who read at least one newspaper is:

$$n(E\cup B)=n(E)+n(B)-n(E\cap B)$$

$$n(E\cup B)=70+73-64=143-64=79$$

Since there are $63$ individuals who do not read either of the two newspapers, the absolute total number of people surveyed is:

$$\text{Total Surveyed}=n(E\cup B)+\text{Number of Non-readers}$$

$$\text{Total Surveyed}=79+63=142$$