functions

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functions

by gmatmachoman » Mon May 03, 2010 3:14 am
1) 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)=9f(v), then
m-v=?
(A) 8
(B) 9
(C) 18
(D) 20
(E) 80
Source: — Problem Solving |

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by liferocks » Mon May 03, 2010 3:41 am
Let v=100x+10y+z

then f(m)=9*2^x.3^y .5^z
or f(m)=2^x.3^(y +2).5^z

hence m=100x+10(y+2)+z

so m-v =(100x+10(y+2)+z)-(100x+10y+z)=20
Ans option D
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