Combinatory Ch 4 #15

by **lisyuan** Mon Sep 08, 2008 12:56 am

I am having problem to understand the problem #15.

On the first step, it excludes the oprtion of not wanting the G.I doll. The calculation was 5!/2!, is this a simplified fomor of

5!/ 2!1!1!1!? Because we have 2 repeated doll, and one for each other 3 types of dolls.

Same for the second step, 4!/2! is a simplified form of 4!/2!1!1!?

by **StudyStrong** Tue Oct 07, 2008 5:35 pm

Could you write out the problem?

Thanks

by **JonathanSchneider** Wed Nov 19, 2008 9:05 pm

Yes, it is simplified from 5!/2!1!1!1! We don't write out the 1! each time, because it has no effect.