If 7/10 is the probability of occurrence of an event
Question:

If 7/10 is the probability of occurrence of an event, what is the probability that it does not occur?

Solution:

We know that,

Probability of occurring = 1 – the probability of not occurring

Given the probability of occurrence

$=\frac{7}{10}$

Therefore, the probability of not occurrence

$=1-\frac{7}{10}$

$=\frac{3}{10}$

Conclusion: Probability of not occurrence is $\frac{3}{10}$