The Prodigious Riddle of Juno

 

 

This ridiculous mess can be sorted into the first statement, which gives a general idea of what's going on, and nine chains of fifteen statements that link a number property to a letter property:

• A person with an even favorite number always has a favorite letter whose maritime signal flag contains red.
• A person with a prime favorite number always has a favorite letter that is typed with the middle or ring finger on a standard QWERTY keyboard.
• A person with a square favorite number never has a favorite letter from the half of the alphabet that makes up the phrase "BOUNDARY LIGHT".
• A person with a triangular favorite number always has a favorite letter that contains a long E sound when spoken in the NATO phonetic alphabet.
• A person whose favorite number is exactly three letters long when written out as an English word always has a favorite letter whose Morse code equivalent's dots outnumber its dashes.
• A person whose favorite number is exactly four letters long when written out as an English word always has a favorite letter that "is for" an eight-letter word in the title of a novel in Sue Grafton's Kinsey Millhone series.
• A person whose favorite number is exactly five letters long when written out as an English word always has a favorite letter that is the one-letter code for a nonpolar amino acid.
• A person whose favorite number corresponds to a non-battery infield position in baseball numbering always has a favorite letter in an even position in the alphabet.
• A person whose favorite number corresponds to an outfield position in baseball numbering always has a favorite letter that is a (non-Y) vowel or a ROT-13 thereof.

From these, one can deduce what a given person's favorite letter must be from their favorite number. For example, 1 is square, triangular, and three letters long when written, and so must have a long E sound in the phonetic alphabet, have more Morse code dots than dashes, and not occur in "BOUNDARY LIGHT"; the only letter that satisfies all three is S.

For 1-9, the favorite letters spell out the answer SELF DRIVE.