Final answer:
The probability of getting a red ball after selecting a blue ball is 11/27.
Step-by-step explanation:
To find the probability of getting the second ball red after selecting a blue ball, we need to take into account the number of red and blue balls remaining. In the given urn, there are 12 red balls and 16 blue balls to start with. After selecting a blue ball, there will be 11 red balls and 16 blue balls remaining. Therefore, the probability of getting a red ball is 11/(11+16) = 11/27.