1997 MIT Mystery Hunt Puzzle 5 Solution

Each of the groups consists of three members of a set. They are:

1. RED SOX, ROYALS, YANKEES (baseball teams)
   ADIRONDACKS, APPALACHIANS, POCONOS (mountain ranges)
   answer: ROCKIES
2. DOONESBURY, DICK TRACY, DILBERT (comic strips)
   PRETZELS, POPCORN, POTATO CHIPS (salty snacks)
   answer: PEANUTS
3. RUTH, SEUSS, ZHIVAGO (doctors)
   CHEKOV, KIRK, MCCOY (original series Star Trek characters)
   answer: SPOCK
4. JEFFERSON, KENNEDY, LINCOLN (U.S. presidents)
   ARIZONA, CONNECTICUT, KANSAS (U.S. states)
   answer: WASHINGTON
5. ENT, HOBBIT, ORC (Tolkein creatures)
   BLACK HOLE, NEUTRON, QUASAR (types of stars)
   answer: DWARF
6. GREEN, PURPLE, YELLOW (colors)
   BROWNSTONE, CORAL, GRITSTONE (rocks)
   ???

It is likely that the rock solution using the obscure GRITSTONE is not the intended answer there, and the result is something that makes ORANGE the answer to that set.

Taking the first letter of the first answer, second of the second answer, etc. as directed, forms REOHFE which anagrams only to the answer, HEREOF.