question_answer

There are 3 bags. Bag 1 contains 2 red and\[{{a}^{2}}-4a+8\] black balls, bag 2 contains 1 red and \[{{a}^{2}}-4a+9\] black balls, and bag 3 containa 3 red and \[{{a}^{2}}-4a+7\] black balls. A ball is drawn at random from at random chosen bag. Then the maximum value of probability that it is a red ball is ______.

Answer:

1/3