Question

How do you evaluate `""_10C_8`?

Answer 1

45

Explanation:

The general formula for a combination is:

`C_(n,k)=(n!)/((k!)(n-k)!)` with `n="population", k="picks"`

and so

`C_(10,8)=(10!)/((8!)(10-8)!)=(10!)/(8!2!)=(10xx9xx8!)/(8!xx2)=45`