Answer:
9.11*10^-4 %
Step-by-step explanation:
To find the probability, you simply need to find the possible outcomes that allows no rooks to be in danger, and the possible amount of ways to place the rooks.
For the first outcome, you start by putting 1 rook in the first columns, you have 8 possible rows to do this. The next rook in the next column will only have 7 possible rows, as you have to exclude the one where the previous rook is located. The next rook, 6 possibilities, the next 5, and so on. So we conclude that the total amount of ways so that none of the rooks can capture any of the other rooks is 8*7*6*5*4*3*2*1 = 8! = 40320
In order to find the total amount of ways to place the rooks, you can just use a combinatoric:
![\left[\begin{array}{ccc}64\\8\end{array}\right]= \frac{64!}{8!(64-8)!} = 4.43*10^9](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D64%5C%5C8%5Cend%7Barray%7D%5Cright%5D%3D%20%5Cfrac%7B64%21%7D%7B8%21%2864-8%29%21%7D%20%3D%204.43%2A10%5E9)
Then:
P = 
Answer: 13.5
Step-by-step explanation:
54/4 = 13.5
13.5 x 4 = 54
Answer: 54678 years
Step-by-step explanation:
This can be solved by the following equation:
(1)
Where:
is the quantity of atoms of carbon-14 left after time 
is the initial quantity of atoms of C-14 in the mammal hide
is the rate constant for carbon-14 radioactive decay
is the time elapsed
On the other hand,
has a relation with the half life
of the C-14, which is
:
(2)
Substituting (2) in (1):
(3)
Applying natural logarithm on both sides of the equation:
(4)
(5)
Isolating
:
(6)
(7) This is the age of the mammal hide