Question

if the probability of events is 2/7 what must be the complement ?

Answer 1

If the probabilty of Event E is p, then,

the probability of Complement of Event E would be "1 - p".

So, to get the complement's probability, we subtract the normal probability from "1".

Hence, the probabilty of the complement would be:

$\begin{gathered} 1-\frac{2}{7} \\ =\frac{7}{7}-\frac{2}{7} \\ =\frac{5}{7} \end{gathered}$