Problem of the Week

May 17, 2008

Problem of the Week: MATHBYJOE  
 
Here is your problem of the week to work that beautiful 
muscle called the brain. Remember: for those of you who 
submit a correct answer, you will be eligible for discounts 
on my collection of ebooks, as well as recognition on my 
website. So good luck, and here's to problem solving.  
Remember, you must work your brain in order that it get 
stronger.  
 
Scientific research done at Stanford University has shown 
that regular mental exercise, such as that performed in 
doing brain teasers, riddles, and the like, improves 
cognitive functioning and brain health. Come work out your 
brain with these fascinating problems and brain teasers.  
 
For the solution, join my free newsletter by clicking on 
the Newsletter Tab. Then email me to let me know. Once I 
receive confirmation that you have joined my newsletter, I 
will send you the solution.  
 
The solution of the last Problem of the Week is as follows: 
Irrational numbers have decimal representations that 
neither terminate nor repeat. All we have to do is come up 
with some kind of decimal which exhibits both behaviors.  
This is quite easy. For example, one such number would be 
0.010010001... where this pattern continues forever.  
Obviously this neither terminates nor repeats since we 
insert an extra 0 each time into the pattern. Once you get 
this idea, you can easily construct an infinite array of 
irrational numbers. Another example would be 
0.12123123412345... in which case you count to the next 
number each time in the pattern. Obviously, this number 
neither repeats nor terminates. By the way, this little 
brain teaser gives a clue as to how you can show that there 
are more numbers between 0 and 1, than all the counting 
numbers. Think about it.  
 
Now for this week: You are offered two choices by a 
friendly genie who wants to give you money. The genie says 
that for the next thirty days you can have either $1 on the 
first day, then $2 on the second day, then $3 on the third 
day, and so on until the end of the thirty days; or you can 
have 1 penny on the first day, then two pennies on the 
second day, then four pennies on the third day, and so on 
until the end of the thirty days. Which option would you 
choose and why?