Monthly Archives: July 2013

Puzzle #8: Number Expressions

Using some digits, say [1, 2, 3, 4], one can form expressions using concatenation of digits (e.g. 34) and arithmetic operations (addition, subtraction, multiplication, division, and unary negation) that evaluate to various values. Examples: 11 = (2 × 4 + 1 × 3), 13 = (42 ÷ 3 – 1), 18 = (23 – 4 – 1)

Form expressions that evaluate to each of the integers from zero through nine. The digits to use are [2, 4, 6, 8].

Submit your answer to Gene Wirchenko . Your answer should be in the form of a proof. That means to show how your answer must be correct. The deadline is Wednesday, July 31, 2013 at noon Pacific Time. I will post the answer shortly after.

Puzzle #6 Solutions: Tents

Spoiler Inside: Solution to Puzzle SelectShow

Other People’s Solutions to Your Problems

Do you have problems? Too many problems? Wouldn’t it be nice to have someone else solve your problems for you?

Nope!

It sounds so good, but often, other people’s solutions do not take into account your needs. Such solutions often become problems themselves.

I had a couple of problems, ah, solutions from the Student Union at my alma mater.

Just before I started attending, they started requiring medical insurance of students. If you did not already have medical insurance, you had to get some through them. This was not in any of the material that I had gotten about costs of attending, and I found out about the requirement only by accident. When I asked how much it would cost, because I needed to know for my funding application, they could not tell me. It delayed my funding application for two to three weeks until I did find out. Their solution was a problem for me.

A second one was when they decided that students should be required to get bus passes. I could not opt out, because I did not meet their gracious requirements for this: one had to live where there was no bus service. I had organised my life so that I rarely had to take the bus; namely, I lived across the street from my alma mater. No matter. I could not opt out of the $40 charge and neither could students who lived in dorms on campus!

That semester, I made one roundtrip bus trip. Without the pass, it would have cost me four dollars, so I had a net loss of $36. It is interesting that the fall semester after I graduated, when I took one course, I used the pass far more. When I was working on my diploma, I did not have the time to make lots of bus trips. Another solution became a problem.

I expect that there were students who benefitted from each of the solutions, but I sure did not.

If you have ever had someone curse you out for your help, maybe you really did not help after all. Consider it before enforcing a solution on someone.

Puzzle #7: Phone Numbers

Chris is rather picky about phone numbers. When selecting one, the final four digits have to be right. Right to Chris means that:

  1. The digits are in one of the following patterns:
    • abac (as in 4549)
    • abcb (as in 2676)
    • aabb (as in 3344)
  2. None of the digits are zero.
  3. a, b, and c need not be distinct. e.g. 4545 fits the first two patterns.

How many combinations are right according to Chris?

Submit your answer to Gene Wirchenko . Your answer should be in the form of a proof. That means to show how your answer must be correct. The deadline is Wednesday, July 24, 2013 at noon Pacific Time. I will post the answer shortly after.

Puzzle #5 Solution: The Back 40

Spoiler Inside: Solution to Puzzle SelectShow

 

The Loud Ones

There can be a lot of volume about some things.  It can be so loud and pervasive that you can get to think that that is where it is at.  Whatever “it” is.

I have found, though, that a lot of times, the volume is masking other things.

Example one: Several years ago, I recall reading some news stories about gaming where it was stated that young males were not the biggest gamers.  Instead, there were a lot of middle-aged women enjoying such games Bejewelled.

If you never look beyond the volume, you can miss such a thing.  There is more than one gaming market.

Example 2: Another aspect to this is that antagonistic people often have the volume turned way up.  Antagonistic people do not do so well with different points of view and keep trying to undermine others.  One way to do this is say lots to drown out others.  That quiet person might not know the most, but it is a pretty good bet that an antagonistic person who keeps belittling others 1) does not either and/or 2) has a spin in what he presents.

This does not mean that every loud person is antagonistic.  One can get excited over something.  To tell the difference, ask yourself how you feel after dealing with a loud person.  If you feel belittled, less, or that the world is not quite as bright as it was, that might well be an antagonistic person.

Volume can be just fine, but volume is not everything.

 

Odd Language #3: Cost Now or Cost Then

From http://www.infoworld.com/d/application-development/what-im-thankful-developer-179748, par. 4: “Developer tools have benefited more from the free and open source software revolution than any other category of software. When I was learning C programming in the early 1990s, Borland’s offer of an integrated MS-DOS C compiler, editor, debugger, and linker for $150 came as a revelation. Developer tools for commercial Unix systems cost thousands.”

Is that “cost” in the present tense or the past tense?  From the article, I think that it is past, but if one does not know the area, it is hard to tell.

Puzzle #6: Tents

It is camping time!  This type of puzzle is called Tents.  This particular puzzle was generated by Tents in Simon Tatham’s Portable Puzzle Collection.

The rules are simple.  Place tents by trees.  Each tree must have a tent adjacent to it either horizontally or vertically.  (A tree can have more than one tent adjacent to it, but only one tree belongs to that one tent.)  No two tents can be adjacent horizontally, vertically, or diagonally.  The number for each row is the number of tents to place in that row.  The number for each column is the number of tents to place in that column.

POTW0809-12pPic

Submit your answer to Gene Wirchenko <genew@telus.net>. Your answer should be in the form of a proof. That means to show how your answer must be correct. The deadline is Wednesday, July 17, 2013 at noon Pacific Time. I will post the answer shortly after.

Puzzle #4 Solution: Lowest Integer

Spoiler Inside: Solution to Puzzle SelectShow