First of all I just wanted to say sorry for the double post, I didnt know where to post my question.

As with the problem...

I was taught a different formula and I think thats what is getting me confused.

I was taught f(x)=n!/x!(n-x)!*p^x(1-p)^n-x

Mr F says: is the same as . In fact, it's the basic formula for
For a and c I got the following result

a)F(x)=5040/144*.064(.6)^4

F(x)=35*.064*.1296

F(x)=35*.0082944

F(x)=.290304 or 29.03%

c)F(x)=(7!) / (2!(7-2)! * (.4^2)(.6)^5

F(x)=[5040/240]*.16(.07776)

F(x)=21*.0124416

F(x)=.2612736 or 26.13%

but I cant figure out b. Should I be solving whereas x=6 since the problem is x>5??

Mr F says: read what I posted for this question.
If so I would get

F(x)=(7!) / (6!)(7-6)! *.4^6(1-.4)^7-6

F(x)=(7)*.004096(.6)

F(x)=7*.0024576 or .25%

but Im not sure if thats the right way to do it.

Any help would be much appreciated

Thanks