User blog comment:Tuner King 5/Help plz/@comment-24808864-20160112230745

The wording of the problem above is incomplete or inaccurate.

The first statement "Suppose 30 people... year of birth." is a discrete problem with a definitive answer. Therefore there is no x that you can find where things are growing fast, because there is no change here, there is just a fixed answer. (The answer, if you are curious, is related to some of our intermediate calculations and would actually be 1-\frac{366}{366}\times \frac{365}{366} \times ... \times \frac{337}{366}=0.7053 <\math> as you note above.