GWD23-Q2

nicboy

    

Q2:

    

The function f
is defined for each positive three-digit integer n by f(n)
= 2^x 3^y 5^z, where x,
y, and z are the hundreds, tens, and units digits of n,
respectively.  If m and v
are three-digit positive integers such that f(m) = 9 f(v),
then m - v =

    

 

    

A.  
8

    

B.  
9

    

C.  
18

    

D.  
20

    

E.   
80

    

Answer:  

问这题思路是怎样的呢，谢谢