Snakes on a math problem

I received an email tonight describing a math problem being prepared for a journal geared towards ‘fun’ math problems for undergrads by Dr. Dan Canada & Dave Goering. I wonder how long it will take the masses to answer it correctly:

There are 100 Snakes and 100 Passengers on the Plane. Each Snake can bite One Passenger (at random). What is the Probability that a Given Passenger - the Target - Does not get bit?

The authors have set up a webpage for the question, that includes the solution (but don’t look, it’s cheating), as well as this harder version of the question:

There are n Snakes on the Plane. There are k Passengers on the Plane. Each Snake will Bite One Passenger at Random. What is the Probability that The Target, Mr. X, does not get bit?

How does the probability compare for different values of n and k?

The authors say it’s not obvious to solve… and I’m not going to try. But you will. Please show your work (and don’t look at the answers… you’re smarter than that).

eta: I'ma' gonna say the first one is approx 36.6%. (I'm pretty sure I did the calculation right.)

We do not like low flow toilets that get clogged

This was one of my pet peeves about the last two apartments I lived at. They're not saving water if you have to flush four times during a single usage of the facilities for fear of clogging the trap!

At first I was dubious about the old public restroom-style toilet with no tank in the current apartment, but it was true love the first time I flushed it and felt the air pressure in the bathroom change.

Yeah, I have an old school no-tank toilet too, and it's wonderful.

All the other plumbing in my apartment is heartache, but man does that flush.

Does it sound weird for a therapist to tell their patient "You are suffering from clinical depression. Your friends won't understand this."

I've never been diagnosed with depression, nor seen a therapist, so it's perfectly possible I'm missing the nuance. But it just looks like it's setting the patient up for isolation where it doesn't need to be. Some friends might not understand, sure. But all of them? Or even to imply a majority? Hardcore.

This toilet does not impress me. Had to replace the seat (it was an instrument of torture,) the cat keeps falling IN and getting water everywhere because the water is so much lower and she isn't that coordinated, tempermental flushing....

People are proving to me that it really doesn't matter what I say as a precaution, they'll blithely do (or ask) stupid things anyway. I don't know why I bother.

eta: ita, yes. Weird and likely damaging.

That's an odd thing to say, ita. There may be a context that is not revealed to you though.

Yeah, ita, that's a very odd way to open that discussion.

There may be a context that is not revealed to you though.

That's what I'd hope. Apparently it resulted in the patient wielding it in a "You're doing exactly what my therapist said you would" way.

Odd. I hope it all turns out okay.

Several things come to mind:

1) the therapist has heard talk from the patient about the friends and feel they have a decent understanding of them

2) the therapist would have been better served saying "most people" instead of "your friends", in which case I think the therapist would be correct

3) the therapist is a tool

4) the therapist knows the patient and made the statement to get a specific reaction

Apparently it resulted in the patient wielding it in a "You're doing exactly what my therapist said you would" way.

Aha. Perhaps the patient in question has some issues of his/her own, and using the therapist's words to back him/her up.

I don't know. People are crazy. Not saying this person you know is, but the brain processes shit in such weird ways I can hardly trust anything I don't witness first hand.