Question

The sum of probabilities of happening and not happening an event is

• A. 0
• B. 1
• C. 2
• D. 0.5

Answer 1

The correct option is B 1

If an event never happen or has never been known to occur ,it is assigned the probability '0'.

If it is certain to happen it is assigned the probability '1'.

Then their sum$=1+0=1$