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 = 
1/2 hr* (5 miles/ 1 hr)= 2.5 miles.
2 1/2 hrs* (5 miles/ 1 hr)= 12.5 miles.
Malia runs 2.5 miles and 12.5 miles in 1/2 hr and 2 1/2 hrs respectively.
Hope this helps~
Well, since we know $3.65 is how much ONE PACK of pencil costs, and k represents the packs of pencils PURCHASED, and x represents the COST per pack, your answer would be A. x = 3.65k. This is because to find out the total cost (x) of k amount of packs, you would multiply the cost (3.65) times k, (known as 3.65k), which would be expressed as x = 3.65k. =)
Hope I helped! ^-^
2 is the answer 23:35677544