The answer is c. I chose the answer c because y=5/2x(I think you forgot to put the x in the question) filled in with the numbers are true while a, b, and d aren't true if filled with 10 and 4.
The number of permutations of the 25 letters taken 2 at a time (with repetitions) is:

The number of permutations of the 9 digits taken 4 at a time (with repetitions) is:

Each permutation of letters can be taken with each permutation of digits, therefore the total number of possible passwords is:
Hi,
o) 357 - 486 = -129
f) 4572 + 609 = 5181
b) -12 - 31 = -43
n) - 15 + 8 = -7
Hope this helps.
r3t40
Answer:
12
Step-by-step explanation:
2+2*5
2*5=10
10+2=12
The answer is any whole number larger than 3