Two or Three

There are 5 counters in a bag. Three are Argentinean (blue) and two are Brazilian (green). Three counters are randomly picked out of the bag, one by one. They are not returned to the bag.

What probability is higher?

A. The probability of choosing three Argentinean counters in a row.

B. The probability of choosing two Brazilian counters in a row and then one Argentinean counter.

Find the answer.

Markov Chain in Every Day Life

The picture shows a subway map.  A team of inspectors verifies passengers’ tickets at a station on a line, or all lines through it if there are many lines.  Then they randomly choose the next neighboring station and move there to make their inspection.

Subway map

How many times higher is the probability of being inspected at station C than at station A?

Are you eager to know the answer? Try yourself before reading how Markov Chain helps to solve the problem. The answer is here.

The perfect explanation is given in the PBS Infinite Series video:

Job Interview Logic Puzzles

JobInterviewLogicPuzzles

Job seekers encounter challenging logic and math puzzles in interviews at high-tech companies. Innovative companies such as Google, LinkedIn, Yahoo, and Microsoft use these types of questions to identify the most intelligent candidates. Microsoft is considered as a pioneer in the interview logic questions. The trend was initially based on Bill Gates’ obsession with puzzles, Fermi problems, and brainteasers. Fermi was known for his ability to make good approximate calculations with little or no actual data.

Winning matters

Puzzles test intelligence. You either get the answer, or you don’t… Logic puzzles divide the world into winners and losers. You get the job you deserve. Recruiters try to identify 3 groups of people 1) who are smart and get things done; 2) who are smart but don’t get things done; and 3) who get things done but are not smart.  It’s better to be on the smart side of the crowd.

How to become smart?

It’s simple. Train yourself like sportsmen build superior strength. Solve logic puzzles every day and never stop. Search for logic puzzles. This is a starter:  “Job Interview Logic Puzzles”  for iPad eBook or the “Job Interview Logic Puzzles” on Amazon. The book includes logic riddles, brainteasers, and spatial thinking questions, training people to confront unexpected questions, to think outside the box, and to elaborate upon non-standard solutions.

Is probability useful in real life?

The question is simple. The best way to answer to the question is to give examples. Here they are:

How many cowboys are expected being alive after a gun fired in a saloon?

How many people in a block building have the same birthday as yours?

How much time do I expect to spend guessing a 5 digit password?

Does a prince have a chance to be chosen by a princess?

How much money does a casino earn everyday?

What is chance that a rocket launch will be successful?

Does a nuclear reactor explode if 4 of 100 its nuts fail?

We don’t use probability on daily basis. Sometimes, simple probabilistic calculations help us to make wise decision and avoid risk. My answer to the title’s question is YES. And yours?