radhika1306 wrote:2. The function f is defined for each positive three-digit integer n by f(n) = 2x3y5z , 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)=9f(v), them m-v=?
(A) 8
(B) 9
(C) 18
(D) 20
(E) 80

the question is wrong .. it should be f(n) = 2^x*3^y*5^z .. see it makes a huge difference ..

Now, it is given that f(m)=9f(v) .. that means the tens digit of m ( that is the power of 3) is two more than the tens digit of v... the rest of the digits( hundreds and units )is the same ..So, the difference between m and v should be equal to 20 .. ans is D ..