If the probability that an event will happen is 5/13, then the probability that will not happen is? a) 5/13 b) 7/13 c) 8/13 d) 10/13

Hi,

Don't forget this:

probability of happening + probability of not happening = 1

5/13 + probability of not happening = 1

5/13 + probability of not happening = 13/13

probability of not happening = 8/13

C

Probability of happening + Probability not happening = 1
Probability of happening = 5/3
Probability not happening = x
Total probability = 1 
5/3 + x = 1
         x = 1 - 5/13
            = 13/13 - 5/13
            = 13-5 / 13
            = 8/13

Therefore, probability of the event not happening is 8/13