According to the problem, the probability that a contestant tried ranking the ground is 0.7 and the probability that a contestant charmed 5-10 worms is 0.3.
So, the probability of A or B happening is-
[tex]P(A\cup B)=P(A)+P(B)-P(A\cap B)[/tex]
Because the events are not mutually exclusive, where
[tex]P(A\cap B)=P(A)\cdot P(B)=0.7\cdot0.3=0.21[/tex]
Then,
[tex]P(A\cup B)=0.7+0.3-0.21=0.79[/tex]Hence, the probability is 0.79.
