Question

Probability of an event $E+$ Probability of the event 'not $E$'$=$_____

• A. $0$
• B. $1$
• C. $2$
• D. $3$

Answer 1

The correct option is B $1$

Let the probability of an event ($E$) $=P\left(E\right)$
Then, probability of not an event ($E$) $=1-P\left(E\right)$
therefore, probability of an event ($E$) $+$ probability of not an event ($E$) $=P\left(E\right)+1-P\left(E\right)=1$