What Are The Odds?

Ok, so it was a Sunday.

A slow day for me as it happens as I only had three clients to 'help'.

So, I go to client #1 and he's fine.  I spend an hour sorting him and a few odds and end out then I make to leave.

He stops me and proceeds to tell a joke ... it's an old one and not one of the best, but I laughed anyway.

That's the kind of guy I am!

I dash off to client #2, do the required business, then we had a chat over a cup of tea (I prefer coffee).  Lo and behold, he tells me the same joke as #1!

He put a different slant on it, but it was, in essence, the same.

I laughed (politely) for a second time then bade him farewell before moving on to client #3.

Now client #3 lives some distance away and the drive to his house was one of the those 'fluffy' experiences that make you want to kill people, but in a loving, 'putting them out of their misery' sort of way.

Yes!  The pensioners were all out for their Sunday 'hold everybody up' by driving at 15 MPH though the countryside drive.

It did nothing for my good humour, but it made me forget that joke.

Anyway, at client #3 I once again 'did the biz' and earned a crust.

Halfway though doing it he tells me he wants me to take him to his son's house for lunch and then said "Oh that reminds me.  He (his son) told me a joke the other day!"

He proceeded to explain that, of course, he'd heard the joke before but that perhaps I hadn't and would like to.

"Go on then." I said.  "Hit me!"

This is it...

    During the war (II) a British Lancaster bomber crew is on their way over Germany 

    to their Target.

    As they get closer, the navigator who doubles as the bomb aimer, starts giving more 

    precise directions to guide them in.

    "Left a bit ... right a bit ... steady ... steady ... right a bit ... left a bit ... Bugger!  Back a bit!!!"

Now, this is where the "What Are The Odds?' bit comes in ...

It was the same joke I'd already heard twice before that day!

So what are the odds that three different people,  that don't know each other and are in three different towns, would tell me the same joke (or variations thereof)?

Mathematicians out there, get scribbling.  Work it out!