15 Choose 0

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Items chosen (k)

What is 15 choose 0?

Answer

15 choose 0 is
1

Order doesn't matter, no repeats: 1 way to choose 0 of 15 items.

There is exactly one way: take none.

C(15, 0) = 15! / (0! · 15!)

= 1

0! = 1 (an empty product), so 15! cancels out completely.

Row sum: 215 = 32,768 — all subsets of 15 items.

See Also

FAQ

What is 15 choose 0?

15 choose 0 is 1

Why is 15 choose 0 the same as 15 choose 15?

Every way to choose 0 of 15 items leaves exactly 15 behind, so choosing 0 and choosing which 15 to leave out are the same count: 15 choose 0 = 15 choose 15 = 1. In the formula n! / (k! (n − k)!) the two factorials below just swap places.

How many ways are there if order matters?

The same 1: with 0 chosen items there is only one order, so P(15, 0) = 15 choose 0 = 1. Order starts to matter from 2 items on: n × (n − 1) arrangements.