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).

>>6
Then scale everything except the new probability, i.e. multiply it by (1 - p) / (sum(X) - p).

Also, you probably should do a proper Bayesian inference instead of pseudo-scientific probability adjustments with no actual basis in statistics.