Welcome to Gene’s Impossible Zoo. The zoo has some four-legged animals (exactly one-half of the number of two-legged animals). The number of two-leggers is exactly one-half of the number of zero-legged animals (often called fish and snakes). These are all of the animals, and they have a total of 200 legs.

It is not called an impossible zoo for nothing. Why is the description above self-contradictory?

Submit your answer to Gene Wirchenko <genew@telus.net>. Your answer should be in the form of a proof. That means to show how your answer must be correct. **The deadline is Wednesday, December 28, 2016 at noon Pacific Time.** I will post the answer shortly after.