Answer:
The probability is 
Step-by-step explanation:
If she has n distinct password candidates and only one of which will successfully log her into a secure system, the probability that her first first successful login will be on her k-th try is:
If k=1

Because, in her first try she has n possibles options and just one give her a successful login.
If k=2

Because, in her first try she has n possibles options and n-1 that are not correct, then, she has n-1 possibles options and 1 of that give her a successful login.
If k=3

Because, in her first try she has n possibles options and n-1 that are not correct, then, she has n-1 possibles options and n-2 that are not correct and after that, she has n-2 possibles options and 1 give her a successful login.
Finally, no matter what is the value of k, the probability that her first successful login will be (exactly) on her k-th try is 1/n
Answer:
$35
Step-by-step explanation:
Using the formula provided, d=(p−c)÷2 (where d is the discount, p is the original price, and c is the store's cost for the dress.) we can determine the discount.
The original price is 120,
d=(120−c)÷2
The store's cost is 50,
d=(120−50)÷2
So we subtract 120 and 50 to get
d=(70)÷2
70 divide by two is
d= 35
The discount is $35
Answer:
12. 9
Step-by-step explanation:
12. Using Pythagoras theorem
let shortest distance be = x
8 square + 5 square = x square
64 + 25 = x square
89 = x square
Therefore x = square root of 89
Thus X = 9
Answer:
1/6
Step-by-step explanation:
There are 6 sides on a dice. Every time you roll you you will have one of those sides. So it is a 1 in 6 chance of you getting 4, meaning that the answer to this problem is 1/6
Substituting -3 for x, we have: (-3)^2-3*-3-7. This simplifies to 9+9-7, or 11.