What are the odds of shuffling a deck of cards into the right order?

Wednesday 22nd July 2009
Submitted by Robert Matthews
Chris Nicolson, Isle of Skye

It depends on how you shuffle them and the cards' order when you start. If you truly randomise the deck, the chances of the cards ending up in perfect order - spades, then hearts, diamonds and clubs - are around 1 in 10 to the power 68 (or 1 followed by 68 zeros). That's a huge number, roughly equal to the number of atoms in our galaxy. Yet card players report it happening. The reason is fresh packs of cards come in perfect order and if they're not shuffled well, can end up back in order. For example, if a dealer riffle shuffles a fresh pack - splitting the deck in two and interleaving the cards together - the pack can end up back where it was after just eight shuffles. Thus, paradoxically, people who aren't very good at shuffling can do a better job of jumbling a pack than those who are.

Is there a formula for generating random numbers?
previous qanda Article
Is anything greater than the sum of its parts?
next qanda Article
Q&A Tabs

Phlegm is the mucous secretion of the respiratory passages. The cilia cells that line these passages are continually driving the phlegm upward to the throat, where it triggers the swallow reflex...

There are two possible explanations why dogs find it hard to hear or recognise your voice over Skype. Firstly, Skype (and voice telephone systems in general) are optimised to transmit frequencies...

Water has a very high volumetric heat capacity. Raising the temperature of a cubic centimetre of water by 1°C takes more than 3200 times as much energy than you’d need to heat the same...

Astronomer Fred Hoyle was the first to point out that if you could drive a car upwards at 95km/h (60mph), it would only take about an hour to get into space. To get to the Moon would take a little...

Until around 100,000 years ago, Europe was dominated by the Neanderthals. But by 28,000 years ago, the last of them had vanished from their final hold-out in Gibraltar, having apparently lost out...

All female mammals have a clitoris, the sole purpose of which is to react to sexual stimulation, and presumably this stimulation has evolved to be pleasurable for most species. But establishing...

To create a sound, we have to set matter - whether it's a gas like air, a liquid or even a solid material - in regular motion, creating a wave of specific frequencies, which we hear as a sound of...

Mirrors don’t reverse left and right either – that’s just our interpretation of what happens. Your reflection in the mirror is actually reversed front to back – if you have...

Discovered by an American student named Gary Flandro in the mid-1960s, the slingshot manoeuvre usually involves spacecraft briefly 'coat-tailing' a planet orbiting the Sun, extracting some of the...

The ice disappears because the wind blows away water molecules that have evaporated or 'sublimed' from the ice, so the ice slowly shrinks in size. The molecules that escape are those with the...

We use cookies to improve your experience of our website. Cookies perform functions like recognising you each time you visit and delivering advertising messages that are relevant to you. Read more here