GWD 18-6

[wingsky]

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

A) 8
B) 9
C) 18
D) 20
E) 80

答案給D, 不過我不知道這題目要怎麼讀耶... 我看不懂他方程式的描述

各位大大幫幫忙吧 3Q

[FrankChang]

某個三位數n的百,十,個位數分別為x,y,z,
某函式f(n)=(2^x)(3^y)(5^z),
目前得知f(m)=9f(v),
(2^X)(3^Y)(5^Z)=9(2^x)(3^y)(5^z),
可知X=x,Y=y+2,Z=z,
m,v百位個位相同,十位數差2,值相差20