Clan x86

General Forums => Entertainment District => Topic started by: Ergot on August 28, 2006, 08:26:54 pm

Title: Simple problem?
Post by: Ergot on August 28, 2006, 08:26:54 pm

In how many distinct ways can three purple and two pink balls be arranged in a row?

I think you guys can figure it out pretty easily... but I'm too stupid to so help :P!

Title: Re: Simple problem?
Post by: deadly7 on August 28, 2006, 09:38:48 pm

Six.

P = purple
I = pink

PIPIP
PIPPI
PIIPP
IPPPI
IPPIP
IIPPP

Incidentally, there's an easier way than thinking about every combination.  Multiply the two numbers.

Title: Re: Simple problem?
Post by: Ergot on August 29, 2006, 02:09:25 am

What about PPIPI, PIIPP, PPIIP, etc?

Title: Re: Simple problem?
Post by: Joe on August 29, 2006, 05:30:45 am

deadly got owned.

Incidentally, Ergot, PIIPP was included. Also, PPIIP is simply PIIPP backwards, but I don't know if you want those or not.

I think the formula deadly gave is the "I have X pairs of pants and Y shirts. How many outfits can I make?" formula. Going by that, we assume the days he's wearing shirts he won't wear pants, and vise versa. Sure, Ergot would like that, but..

Title: Re: Simple problem?
Post by: iago on August 29, 2006, 09:34:49 pm

10, I think?  That includes ones that are backwards-versions of other ones:

PPPII
PPIPI
PIPPI
IPPPI
PPIIP
PIPIP
IPPIP
PIIPP
IPIPP
IIPPP

Title: Re: Simple problem?
Post by: Newby on August 29, 2006, 10:48:08 pm

That's a combination or permutation or some shit like that. :(

Title: Re: Simple problem?
Post by: Ender on August 29, 2006, 11:40:13 pm

It's ten. The algebraic way of doing this (combinations) is 5! / (3!2!). There are 5! permutations and you have to divide by 3! because there are 3! arrangements of three purple balls in a row and 2! arrangements of the whatever-color ball in a row and those produce non-distinct permutations.

Title: Re: Simple problem?
Post by: Ergot on August 30, 2006, 12:08:55 am

Quote from: Ender on August 29, 2006, 11:40:13 pm

It's ten. The algebraic way of doing this (combinations) is 5! / (3!2!). There are 5! permutations and you have to divide by 3! because there are 3! arrangements of three purple balls in a row and 2! arrangements of the whatever-color ball in a row and those produce non-distinct permutations.

OMG YOU'RE SO SMART x_x! I never learned that in algebra :(.

Title: Re: Simple problem?
Post by: Newby on August 30, 2006, 09:40:00 am

Hehe. I forgot everything I learned in pre-calc already. :(

Title: Re: Simple problem?
Post by: Joe on August 30, 2006, 12:57:33 pm

I forgot how to figure premutations. :(

Title: Re: Simple problem?
Post by: Ender on November 08, 2006, 07:05:33 pm

You forgot how to spell them, too.

Title: Re: Simple problem?
Post by: Chavo on November 10, 2006, 12:30:02 pm

Either that or he really doesn't know how to recognize the factors preceding a mutation :P