Probability change

Suppose i have a set [A,B,C]
Probability of A =10% B=40% C=50%
If probability of C lowers to 25%, how the remainder value is distributed(proportionaly)?
I know it suppose to get like 15(+50%),60(+50%),25 but what if the set grows?
exmaple       5,77,3,15(-5) becomes 6.65,102,4,10
I'm looking for a formula for arbitrary sets of probability(not just 3).

>>11
depends on post rate, close to 100%.
If you select threads off the front page its 100%. Regardless its zero-effort dubs, unlike imageboards where you adaptive post rate adjustments(take whole board average post rate and predict the next number based on current) to create the possibility of dubs.