In the row of Pascal's triangle that starts 1, 11, what is the ninth number?
165
8)
This will be the 11th row of the triangle [ where the first "row" = 1 is termed row "0" ]
The rth number on the nth row is given by C(n, r - 1)
So the ninth number on this row will be given by
C (11, 9 - 1) = C(11,8) = 165