## Two Truths and A Lie

2010-06-29

I just tweeted a
very *interesting* two truths and a lie:

- P=NP
- All even numbers greater than 2 are sums of primes
- The logical conjunction of the above two

I'll leave the solution to the reader. It occurred to me while lying in
bed, however, that it should be possible to make a list such that *any
of the three* can be the lie. After a little thought and some trial and
error, the following fits the bill:

- One of the following two statements is false
- One of the other two statements is false
- One of the previous two statements is false

Simple, but it works. Neat.

This reminds me of the riddle in Inside Man:

Which weighs more: all the trains that pass through Grand Central Station [in NYC] in a year - or the trees cut down to print all U.S. currency in circulation? Here's a hint: It's a trick question.

Once again, I leave the solution as an exercise to the reader... or you can watch the movie.

EDIT: here are a few more humorous Two Truths and A Lie's I came up with:

- Water is wet
- Fire is hot
- The cake

"well, *obviously*, the cake is a
lie."

- You think this one is true
- You think the last one is probably the lie
- You're not sure anymore

What?

- Either you won't answer, or you'll answer correctly
- Either you won't answer, or you'll answer incorrectly
- You will answer

Interestingly, it's possible to correctly answer this last one. You can figure out how.