A very merry Christmas to all our listeners. We're hoping to record one more seasonal themed podcast before Santa comes, so let us know your Christmas mathematical questions in the comments below.

Christmas card with apologies to Hilbert, all major churches, and humour in general.

I have two children. One of them is a boy who was born on a Tuesday.

What is the probability that both children are boys?

Although very similar, the answer turns out to be 13/27, which is quite different. However, Ben got confused when giving the answer during our pi podcast and paid penance by making a video

However, there is still some debate about the answer.

Join us this week as we record all from the same location and try and tease apart the complexity of weird conundrum.

In this (Hallowe'en themed?) episode we watch the movie Moneyball.

The story of a young mathematician, played by Jonah Hill, struggling to be heard amongst the angry men that make up baseball. And I think Brad Pitt was in there somewhere as well.

Can Jonah produce a winning team by redefining how statistics are used?

Why does Thomas keep saying the phrase "dick swinging"?

Where did Ben get a hold of those baseball sounds?

All of these questions and more are not answered in our Moneyball podcast.

If you're interested in watching Moneyball you can follow the Amazon link below.

Although there was no Dev Patel, or tigers in this pi, we still managed to squeeze a boat into this week's puzzle.

This puzzle is a variant on an old favourite. We don't have chickens, corn, or foxes, but we still want to cross a river. Here's the question:

A husband and wife come to the edge of a river, where they find two children with a small boat. The boat can hold either one child, two children, or one adult. How do you get everyone across the river in the minimum possible number of crossings?

Post your answers below, and we'll give you the answer in the next podcast!

Sadly there were no tigers, boats or Dev Patel in this movie.

Nope, this film was an avant garde, mood piece, seething with questioning the meaning of truth and its place in the lives of humans and the universe.

In other words pretentious.

However, none Darren Aronofsky's nonsense matters. What you should be listening for is Ben's rendition of "Euclid's people" a song of his own creation sung to the tune of "Common people" by pulp.

You've got to hear it to believe it.

If you're interested in watching pi you can follow the Amazon link below.

I have two children. One of them is a boy and they were born on a Tuesday.

What is the probability that both children are boys?

This is a hard question, and Ben ****ed up the explanation when he tried to do it live. So, as penance, we made him sit down and explain it as a video.

Here's a simpler question written out much nicer:

I have two children. One of them is a boy.
What is the probability that both children are boys?

Now you may think the probability is 50%, but that is not so (note that we are assuming that boy and girl births are equally likely). The reason is because we have more information about the children.

Suppose we denote a boy by "b" and a girl by "g". Further, we capitalise the letter to denote the elder child. In this way we could have the following combinations of children:

Bb

Gb

Bg

Gg

However, we know we have at least one boy, so we can't have Gg. Out of the possibilities that are left, namely Bb, Gb and Bg, there is only one way to get two boys, the chance is 1/3! Counter-intuitive no?

Note that if we had posed the problem as I have two children and my eldest is a boy then (using the above argument) the probability of have a second boy is then 1/2.

Probability can be a tricksy animal. Even for a Cambridge educated lecturer!