Answer:
1/6
Explanation:
The probability of an event happening k times in n trials if the probability of the event is called p is the binomial distribution probability:
P(k times in n trials) = (Ckn)pk(1-p)n-k where the 1st term is the combination of n things k at a time or
n!/(k!(n-k)!)
In this case n is 100, k is 25 and P = 1/6
Hope that helps.