SEND MORE MONEY

One time in college I emailed my dad asking for money and he said I could have some if I solved the following equation:

   SEND
+MORE
_______
MONEY

Each letter represents its own digit (0-9) and multiple occurrences of the same letter represent the same digit (eg if one of the E's represents a 3, they all do).

A Boat in a Tank

Imagine you are in a small rowboat floating in a swimming pool.  There's a big rock in the boat and you drop it overboard. Does the water level rise or fall?  Why?

The Magic Square

This is one I come back to when I'm bored and all I have is pen and paper.  I also read in a biography of Benjamin Franklin that he used to do this when he was stuck in boring meetings.  Construct a 3x3 grid of numbers, using numbers 1 through 9, and arrange the numbers in the square such that every row, column, and diagonal (diagonals through the center) adds up to 15. 


Too easy?  Now construct a 4x4 grid made out of numbers 1 through 16, such that every row, column, and diagonal adds up to 34.  This one is killing me because I figured it out once, but can't seem to rediscover the solution.  There are ways to do this for grids 5x5, 6x6, and up, though they no doubt get very difficult.

No Riddle This Week

I can't think of any and I'm too busy with work, sorry everybody. 

4=5

The other day, someone in our creative services department tried convincing me that 4=5.  He offered a convincing proof, which is displayed below.  But what is wrong with it? 

Pirates, Part 2

Again, taken from folj.com. 

The five pirates mentioned previously are joined by a sixth, then plunder a ship with only one gold coin.


After venting some of their frustration by killing all on board the ship, they now need to divvy up the one coin. They are so angry, they now value in priority order:

1. Their lives
2. Getting money
3. Seeing other pirates die.


So if given the choice between two outcomes, in which they get the same amount of money, they'd choose the outcome where they get to see more of the other pirates die.


How can the captain save his skin?

The Blind Date Bachelor

(Modified from a puzzle about a sultan and his harem I heard from Jon Huang.) The Blind Date Bachelor is the newest dating show, in which where there is 1 bachelor and 4 contestants trying to win his heart. He will meet each contestant for the first time on a blind date. At the end of the date, he must choose whether to marry her or never see her again. If he marries her, the game is over. If he rejects her, he is set up on a date with the next contestant and repeats the process. If he rejects the first 3, he marries the last one automatically. He is able to compare and rank contestants that he has already met, but will not know for sure who he likes best until he has met them all. It's very important that he marry the best one, or he will spend the rest of his life wondering what could have been. What strategy will maximize his chances of finding the best mate-for-life?

3 Bonus Questions: What is the probability of winning using the best strategy?  What if there are 5 contestants, not 4?  And finally, what if there are n contestants?