User blog comment:BonesMcGee/Brainstorm: Potential savings in using the hurry hatch trick/@comment-5116140-20120803001445/@comment-5116140-20120804003335

Well, after all that statistics, notice how the math of the geometric series spits out almost exactly the same number you arrived at intuitively.

Bones: "So even if it took you 50 attempts (250 x 50 coins = 12,500) and all you got was a Dimetrodon (tier 1), you still saved 200 coins and a lot of time when compared to starting from scratch."

versus the geometric series estimate of 11,500 = 250/p

That is less than a 10% error. Well done!