Answer:
312
Step-by-step explanation: You need to multiply your numbers and I don't know if you got my numbers.
There are 4 possible letters to start with.
The pass word is 3 letters long.
The first letter can be A, B, C, D = 4 different letters.
The 2nd letter can be 4 - 1 = 3 letters ( Can't have repeats)
The 3rd letter can be 3-1 = 2 letters ( no repeats)
Number of possible passwords = 4 x 3 x 2 = 24
I don't know the root you are talking about but i would say "we might say that they are bulk"
2/30=0.06 repeated. 0.06=6%. 7% or 6.6% of the 30 families have 4-5 pets.