How many combinations of 8 numbers are possible from 10 numbers?

Answer 1

In general, the number of combinations of n things taken r at a time is

nCr = n!/[(n - r)!r!]

Thus, we have:

10C8

= 10!/[(10 - 8)!8!]

= 10!/(2!!8!)

= (10 x 9 x 8!)/(8! x 2 x 1)

= (10 x 9)/2

= 5 x 9

= 45