A bakery produces six different kinds of pastry, one of which is eclairs. Assume there are at least 20 pastries of each kind.

a) How many different selections of twenty pastries are there?
I was thinking combinations with repetition and order doesn't matter, so (n+r-1 r) but I'm not sure where n=120 and r=20?

b) How many different selections of twenty pastries are there if at least three must be eclairs?
(n+r-1 r) = (120+20-1 20) = (139 20) (20 3) ???

c) How many different selections of twenty pastries contain at most two eclairs?

(139 20) (20 2) ??

Question

A bakery produces six different kinds of pastry, one of which is eclairs. Assume there are at least 20 pastries of each kind. 

a) How many different selections of twenty pastries are there? 
I was thinking combinations with repetition and order doesn't matter, so (n+r-1 r) but I'm not sure where n=120 and r=20? 

b) How many different selections of twenty pastries are there if at least three must be eclairs? 
(n+r-1 r) = (120+20-1 20) = (139 20) (20 3) ??? 

c) How many different selections of twenty pastries contain at most two eclairs? 

(139 20) (20 2) ??

anonymous · Answer

Ask in Maths

anonymous · Answer

I did :( But no one knows how to do it :/

anonymous · Answer

I think the language in this one is rather confusing.

farmdawgnation · Answer

This looks like combinations and permutations. I've done those before, but it's been a few years. I think myininaya might be able to help you out. You should leave her a fan testimonial and ask her to look at this question.

farmdawgnation · Answer

I don't know if she's online right now, but she should be more than happy to help when she comes online.

anonymous · Answer

Okay thank you so much for your input :D