Magic: the Gathering in the UK
play the following mana base:
chance of drawing each card in your opening hand:
1/5 per card (a little less for island)
so with 7 cards... that would be a 7/5 chance per card in opening hand (or a little over 1 each time... so sometimes you will get 1, and sometimes 2)
by turn 5 you will have seen 12 cards, so 12/5, you are guarenteed to hit all your colours
halve the number of each card played in your deck, will reduce the probability by half:
so, a 6/5 chance of seeing each basic land by turn 5
10 lands: 6/5
9 lands: 5.4/5
8 lands: 4.8/5
this means that a mana base of:
has a 96% chance of seeing all 5 lands out on turn 5
whilst if you play 9 of each type, that will give you a 104% chance, or a 4% chance more than certain
go with 9 of each type, to be safe....
or alternate between 9 and 8 every game (a little more fiddly, but the actual optimal configuration)
Hahaha! AdditionalI constraints: I have to play all 35(?) legal Commander cards with WUBRG on them and I also want to win, at least sometimes !
Pentad prism should probably be in there- T3 bringers in limited!