Book Review - How Would You Move Mount Fuji?

I just finished How Would You Move Mount Fuji? - Microsoft's Cult of the Puzzle by William Poundstone. It's about Microsoft's (and other companys') interview testing where they throw 'impossible' puzzles at applicants. I checked it out just to see if I could answer the puzzles (I'll give you an example question and its answer later.) I have to confess I couldn't figure them all out.

There's more to the book than just the puzzles, however. Poundstone discusses the pros and cons of hiring based on how someone responds to these tests. Many companies don't even care if the applicants get the right answer, they're more interested in seeing the logic used to get the answer. He also goes into detail on Microsoft's hiring process specifically, and doesn't seem to be all that impressed by it. There's also a section on how to outsmart the puzzles which would be helpful if you were ever put into this situation.

Here's the promised example:

You have five jars of pills. All of the pills in one jar only are contaminated. The only way to tell which pills are contaminated is be weight. A regular pill weighs 10 grams; a contaminated pill is 9 grams. You are given a scale and allowed to make just one measurement with it. How do you tell which jar is contaminated?



Answer:

Call the jars #1, #2, #3, #4 and #5. Take one pill from #1, two from #2, three from #3, four from #4 and five from #5. Weight the whole lot. Were all the pills normal, the results would be 10+20+30+40+50 = 100. In fact, the weight must fall short of this by a number of grams equal to the number of the contaminated bottle. Should the total be 146 grams (4 grams short), then bottle #4 must contain the lighter pills.

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