Lots of eyes, lots of muscles

Inevitably, there comes a time when, convinced that there's something there to find, the whole party all search the same place to make sure that somebody picks up something that everyone else has missed, or all try to open the same stuck door, or pick the same lock, or find the same traps, or whatever. Apart from the fact that it takes up valuable time, and thus increases the chance of being mutilated by some treasure-less wandering monster, it can certainly help swell the party's coffers.

Assuming there really is anything to be found, that is.

Of course you can always throw a die for each individual searcher (I like to use a different coloured d6 for each character so I know who has and hasn't succeeded, just in case they want to keep the news to themselves or something, the sneaky bastards).

However, if you want to skip over all that and get the show on the road, you can always convert all those individual rolls into one combined d100 roll.

The formula for finding the probability from a whole bunch of d6 (or any other die type) is this:

1 - [(chance of NOT showing the desired pips) to the power of (the total number of dice)]

Assuming that you might just want to know the numbers and not have to do a whole lot of tedious maths to find out, here are some I prepared earlier:

Number of d6	Chance of at least one 6 showing on a handful of d6: 1 - [(5/6)^N]	Chance of at least one 1 OR 2 showing on a handful of d6: 1 - [(2/3)^N]
1d6	16.7%	33.3%
2d6	30.6%	55.6%
3d6	42.1%	70.4%
4d6	51.8%	80.2%
5d6	59.8%	86.8%
6d6	66.5%	91.2%
7d6	72.1%	94.1%
8d6	76.7%	96.0%
9d6	80.6%	97.4%
10d6	83.9%	98.2%
11d6	86.5%	98.8%
12d6	88.7%	99.2%
13d6	90.6%	99.4%
14d6	92.2%	99.6%
15d6	93.5%	99.7%
16d6	94.6%	99.8%
17d6	95.4%	99.89%
18d6	96.2%	99.93%
19d6	96.9%	99.95%
20d6	97.4%	99.96%