There are 36^7 different passwords available, incluiding ones that have repeated characters, are sequential characters, or are all the same letter or digit. Of these 26^7 are invalid. the probability of obtaining a valid password is
... 1 - 26^7/36^7 ≈ 0.8975
What kind of sheet is the sheet that she wants to buy?
D - their slopes are negative reciprocals of each other.
