Given that the box has \[5\] blue and \[4\] red balls.
Let us consider \[{{E}_{1}}\] be the event that first ball drawn is blue and \[{{E}_{2}}\] be the event that first ball drawn is red.
And, E is the event that second ball drawn is blue.
Now, the probability of E is:
Therefore, the required probability is \[5/9\].