Answer:
The probability is 
Step-by-step explanation:
We can divide the amount of favourable cases by the total amount of cases.
The total amount of cases is the total amount of ways to put 8 rooks on a chessboard. Since a chessboard has 64 squares, this number is the combinatorial number of 64 with 8,
For a favourable case, you need one rook on each column, and for each column the correspondent rook should be in a diferent row than the rest of the rooks. A favourable case can be represented by a bijective function
with A = {1,2,3,4,5,6,7,8}. f(i) = j represents that the rook located in the column i is located in the row j.
Thus, the total of favourable cases is equal to the total amount of bijective functions between a set of 8 elements. This amount is 8!, because we have 8 possibilities for the first column, 7 for the second one, 6 on the third one, and so on.
We can conclude that the probability for 8 rooks not being able to capture themselves is

It would be 9!!!
Hope that helps!!!
probability of drawing ace: 4/52 = 1/13
probability of drawing 9: 4/52 = 1/13
probability of drawing ace or 9: 1/13 + 1/13 = 2/13 or ~15.4%
Answer:
8
Step-by-step explanation:
let the numbers be x,x+1,x+2
x+x+1+x+2=27
3x+3=27
3x=27-3=24
x=24/3=8
Answer:
$6.39
Step-by-step explanation:
Just add the cost of everything
3.18 + 1.25 + 1.96 = 6.39