A speedy player

Spanish version: El deportista veloz

 The other day, in an interview to a television channel, the famous rugby player Richie McCaw, the current captain of the All Blacks, New Zealand's rugby team, has made some startling statements: 'The day before yesterday I was 31, and next year I will be 34'.

No doubt Richie McCaw is a very quick sportsman, but not enough to meet the years as fast as he says.

Or do you think he may be telling the truth?

 It seems incredible, pero his statements are true.

First, we must know that Richie McCaw was born on December  31, 1980.

And we have to keep in mind that the interview took place on January 1, 2013.

So when he says 'yesterday', he is referring to 2 days before January 1, that is December 30, when he still was 31. The day before the interview, December 31, turned 32.

During this year 2014, on December 31, he will be 33.

And 'next year', on December 31, he turns 34.

So it was true what he said in his interview. A speedy player in the pitch and in celebrating his birthdays!

A puzzle of cycling

English version: Contrarreloj ciclista

The men's individual time trial of the UCI Road World Championship takes place today.

The trial participants start out one at a time

We know that among the first 30 participants, 15 are Americans and the other 15 are Europeans.

How many cyclists have to leave so that we make sure that there are 2 of the same continent racing the trial?

Simply 3 cyclists.

If the first 2 are from the same continent, either European or American, then they'll have fulfilled the condition of having 2 riders on the same continent performing the test.

And if they are from different continents, one European and one American, the third cyclist will necessarily coincide with one of the 2 first cyclists, since we know that in the first 30 participants there're no runners from other continents.

The only difficulty with this problem is to be aware of what is being asked. There are people who answer that we need 16 cyclists racing on the road, as they interpret the question the wrong way, and they believe that the question is: how many cyclists must be out to ensure that at least 2 cyclists from different continents are racing the trial?

 

So we conclude that if we want to answer the question correctly, we must pay a care attention about  which is exactly the question.