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# Is 1 the correct answer to this question?

There are 15 pastries available at a cafe. From these, Mitzy is to choose 13 for her party. How many groups of 13 pastries are available?

### 10 Answers

- Anonymous1 month ago
Can she have multiples of the same kind?

If she can there’s 15^13 possibilities

If not there are 15 nCr 13 possibilitiesa

- ?Lv 61 month ago
I see how you got the answer, but I don't think 1 is the answer they are looking for.

a) There are 15C13 = 105 groups of 13 pastries available to Mitzy to choose from at the cafe. This is the answer everyone has given you, because that is surely the question being asked.

b) Once she makes her choice of the 13 and brings them to the party, there will indeed be 1 group of 13 available to those at the party. But that's not the question that's being asked.

- Anonymous1 month ago
Probably

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- PuzzlingLv 71 month ago
You have 15 items and you are choosing 13 of them. So you want to calculate "15 choose 13".

If you just want the answer, type "15 choose 13" into Google and you'll get the answer. [see link at the bottom].

If you want help in solving similar problems in the future, keep reading. The formula for "n choose k" is:

C(n,k) = n! / ((n-k)! k!)

We could plug in n=15, k=13 and we'll get:

C(15,13) = 15! / (2! 13!)

But notice that picking 13 pastries for her party, that's the same as picking 2 pastries to NOT have at her party. In other words:

C(15,13) = C(15,2)

It's easier to calculate combinations for smaller numbers:

C(15,2) = (15 * 14) / (2 * 1)

= 15 * 7

= 105

Answer:

105 ways

Source(s): https://www.google.com/search?q=15+choose+13 - ?Lv 71 month ago
15! 15!

15C13 = ------------------ = ---------

13! (15-13)! 13! 2!

15 • 14

= ----------- = 105 (assuming NO repetitions)......ANS

2 • 1

- az_lenderLv 71 month ago
Since she will omit only 2, it's easier to figure out in how many ways she can choose 2 to omit. The answer is 15*14/2 = 105.

- 1 month ago
No, that’s not correct. You’re dealing with discrete mathematics and the subject of “Combinations”

Quickly imagine taking 13 from a group of 15. That’s one way. Exchange one of the pastries for one you didn’t choose yet and there’s another way right there. And so on...

Hint: there’s a heck of a lot more than one or two!

Double hint...there’s more than a hundred ways

- KrishnamurthyLv 71 month ago
There are 15 pastries available at a cafe.

From these, Mitzy is to choose 13 for her party.

How many groups of 13 pastries are available?

binomial(15, 13) = (15!)/(2! 13!) = 105

- Anonymous1 month ago
yes.............................................................