tengo correo

Me escribe tan poca gente que cuando me llega un correo me emociono y me pongo supercontento y me da un ansia tremenda de responder con todo el ímpetu posible.

Así que me he puesto contentísimo cuando he recibido un correo del señor de la foto o de alguien que se llama exactamente como él. Me ha escrito en portugués, así que yo le he respondido en inglés.

Su correo, en portugués, decía esto (salvo por la imagen del calendario, que era otra, pero yo pongo esta que queda más clarita):

From: cicero assis
To: me
Subject: Enc: Julho/2011

Boa Sorte!!!

Este ano, Julho terá 5 sexta-feiras, 5 sábados e 5 domingos.

Isto acontece uma vez a cada 823 anos. Estes anos são conhecidos como 'Money bag'.

Passe para 8 boas pessoas e o dinheiro aparece em 4 dias, baseado no Fengshui chinês.

Quem parar não recebe, diz aqui...
Bom, não custa tentar....

A lo que yo, en inglés, he respondido esto:

From: me
To: cicero assis
Subject: Re: Julho/2011

Hello, Cicero.

First of all forgive me in advance for replying you in English: I consider myself allowed to, as you wrote me in Portuguese, being a language I don't speak nor write.

Secondly, I think I grasped that you were saying that 2011 was an unusual year as this year July have 15 days who are either friday, saturday or sunday which according to your mail only happens once every 823 years. That would mean that this would happen, for any given year, 0.00125% of the time, and that the last time it happened would be around the year 1188 (that would had been quite odd if you consider that we weren't even using the calendar we use today, the Gregorian Calendar in 1188, since it started being used in 1582), and the next year in which this happens would be around the year 2834.

I'm sincerely interested in knowing what math you did to get that numbers: being a mathematician myself, and noticing the fact that July always had, have and will always have 31 days, I would expect this 10 weekend days plus five fridays thing to happen once every seven years, being that those in which July starts on friday, as this is. This would mean that it happens about 14.29% of the time, going that percentage a bit up or down with leap years (but, being placed steadly, at the long run that won't change that percentage quite much).

For example, this happens this year, but happened also in 2005 and in a total of 14 years of the XX century (1994, 1988, 1983, 1977, 1966, 1960, 1955, 1949, 1938, 1932, 1927, 1921, 1910 and 1904), which for a total of 100 years gives a 14% chance of the circunstance happening for every year, which is pretty closer to my numbers than to yours.

And lastly, I would appreciate if you could stop sending me unsolicited spam of every kind, and specifically if it contains stupidities like this.
Regards,

-Dave.

P.S. July will have again 5 fridays, saturdays and sundays in 2016. When that year comes you should consider not bothering people pretending to tell them how rare that thing is (and actually telling them just that you can't count), but if you do start correcting your data and just say that it didn't happened for 5 years, not eight centuries.