Can you solve this for me? Please

Question

"the car plate number contains 3 distinct letters where the first letter is "Z" followed by 3 digits which are not necessarily distinct. How many car plate number can be produced? "

Answer 1

Z _ _ _ _ _

Since the letters must be distinct, there are only 25 choices

for the second letter and 24 for the 3rd letter.

There are 10 choices for each digit

25*24*10*10*10 = 600000