Hello, I am reading some notes and there is this statement that says:
"The possible passwords , with length k, if you use only CAPITAL letters and at LEAST one number is36^k - 26^k ".
I understand this, but before reading the solution i had found one of my own.
k * 10 * 36^(k-1)
that is because, if the number is in the first spot, you have 10 digits to chose for the first and 36 for the rest of the positions
10 *36(k-1)
if the number is in the second place 36*10*36(k-2) etc.
the number can be in all k spots so k * 10 * 36^(k-1).
This does not produce the same result, but i don't understand why.
"The possible passwords , with length k, if you use only CAPITAL letters and at LEAST one number is36^k - 26^k ".
I understand this, but before reading the solution i had found one of my own.
k * 10 * 36^(k-1)
that is because, if the number is in the first spot, you have 10 digits to chose for the first and 36 for the rest of the positions
10 *36(k-1)
if the number is in the second place 36*10*36(k-2) etc.
the number can be in all k spots so k * 10 * 36^(k-1).
This does not produce the same result, but i don't understand why.