What is the probability that, in a class of 30 students, exactly two of the students have their birthday on the same day (defined by same day and month) (assuming it's not
![Answer to Riddle #55: Free theatre tickets to the first person in the line with the same birthday as someone in front of them in the queue. Answer to Riddle #55: Free theatre tickets to the first person in the line with the same birthday as someone in front of them in the queue.](http://puzzles.nigelcoldwell.co.uk/images/55eq1.png)
Answer to Riddle #55: Free theatre tickets to the first person in the line with the same birthday as someone in front of them in the queue.
![Answer to Riddle #55: Free theatre tickets to the first person in the line with the same birthday as someone in front of them in the queue. Answer to Riddle #55: Free theatre tickets to the first person in the line with the same birthday as someone in front of them in the queue.](http://puzzles.nigelcoldwell.co.uk/images/55eq2.png)