Monthly Archives: September 2014

Puzzle #68: Binders

You are taking five courses this semester: one English, one Math, and three Computing courses. You bought six binders for notes, one for each course plus one for general notes.

How many ways can you allocate binders to courses and general notes
1) So that each binder colour is used for only one course subject?
2) So that each course subject has only one binder colour?
for these scenarios:
1) You bought three red, two blue, and one green binder. (Yes, “binder” is correct. My thanks to Sara Wolfe of Thompson Rivers University’s Writing Centre.)
2) You bought two red, two blue, and two green binders.

For each question, the general notes binder is not for a course, and each course in a subject should be considered distinct, but the binders of each colour are not distinct from each other.

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, September 24, 2014 at noon Pacific Time. I will post the answer shortly after.

Puzzle #66 Solution: Carrying Stuff

Spoiler Inside: Solution to Puzzle SelectShow

And On and On

Do we ever learn? Yes, but it might be a while.

The C programming language has a number of language features that are awkward or even dangerous. These features have been used in substantially the same form in many other languages.

One example of this is the switch statement which allows for the choosing of one of a number of sections of code to be executed. In any other language that I have used (barring those borrowing switch from C), after the chosen code is executed, execution continues after the switch.

Not in C! Execution falls through to the next statement (which unless the choice just executed was the last one) is part of another choice. This is almost certainly not what is wanted, but one has to put a break statement to force execution where one wants it over 99% of the time.

Some nasty programming errors have occurred because of this stupid language feature, but let a new language have a switch statement, and the chances are good that it will “work” this same silly way.

It sure would be nice to have more programming languages that do not insist on making it easy to shoot oneself in the foot.

Odd Language #64: Terms That No Longer Fit

Have you read any comic strips lately? Do you have a cellphone?

The issue: Some terms do not apply any longer or necessarily.

Many “comic strips” are not comic and do not come in strips. It may have been true or mostly true a long time ago, but it is not very applicable today. Nonetheless, the name sticks.

If you have a portable phone that does not operate on cellular technology, what do you call it? Probably a cellular phone anyway. What should you call it? A far better term for “cellphone” is “mobile phone”. That is the term that I heard used when I was in China back in 2002. I hear it occasionally here in British Columbia. It makes more sense to me.

Puzzle #67: Coloured Blocks

You have ten blocks with each block being a solid colour of one of red, orange, yellow, green, blue, and violet.

1. There are the same number of blue blocks as yellow blocks.
2. The number of green blocks is not prime.
3. There are fewer yellow blocks than orange blocks.
4. There is at least one block of each colour.
5. There are the same number of violet blocks as orange blocks.
6. There is exactly one red block.

Given the above, how many blocks are there of each of the six colours?

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, September 17, 2014> at noon Pacific Time. I will post the answer shortly after.

Puzzle #65 Solution: Socks

Spoiler Inside: Solution to Puzzle SelectShow