Guest Posted October 30, 2009 Report Share Posted October 30, 2009 (edited) F(x) denotes the absolute difference between SOD(x) and SOD(x+2), whenever x is a positive integer. Determine the total number of distinct values of F(x) < 2000. Note: SOD(x) denotes the sum of digits in the base ten representation of x. Edited October 30, 2009 by K Sengupta Quote Link to comment Share on other sites More sharing options...
0 Guest Posted October 31, 2009 Report Share Posted October 31, 2009 2 , 7 , 16 , 25 Quote Link to comment Share on other sites More sharing options...
0 Guest Posted October 31, 2009 Report Share Posted October 31, 2009 @3ala2, there are more values of F(x) 2,7,16,25,34,.......i.e., 2, 7+9*n, n=0,1,2,....110 therefore there are 112 values of F(x) Quote Link to comment Share on other sites More sharing options...
0 Guest Posted October 31, 2009 Report Share Posted October 31, 2009 @3ala2, there are more values of F(x) 2,7,16,25,34,.......i.e., 2, 7+9*n, n=0,1,2,....110 therefore there are 112 values of F(x) mm.. i agree with ur method.. F(x) can go till 2000 which means n can reach 221 then we get 223 value for F(x) Quote Link to comment Share on other sites More sharing options...
0 Guest Posted October 31, 2009 Report Share Posted October 31, 2009 I am so lost. Could someone please give me a quick example of F(x) in action and how it does, or does not, fit into the solution we are supposed to look for. Thanks! Quote Link to comment Share on other sites More sharing options...
0 plainglazed Posted October 31, 2009 Report Share Posted October 31, 2009 x=9;SOD(9)=9;SOD(9+2)=SOD(11)=1+1=2;f(x)=abs(9-2)=7 Quote Link to comment Share on other sites More sharing options...
0 Guest Posted October 31, 2009 Report Share Posted October 31, 2009 mm.. i agree with ur method.. F(x) can go till 2000 which means n can reach 221 then we get 223 value for F(x) Yaa... I thought F(x)should be less than 1000 ... thanks for verifying Quote Link to comment Share on other sites More sharing options...
0 Guest Posted October 31, 2009 Report Share Posted October 31, 2009 (edited) Fun puzzle. Where do you get so many puzzles, K Sengupta? Edited October 31, 2009 by xamdam Quote Link to comment Share on other sites More sharing options...
0 Guest Posted October 31, 2009 Report Share Posted October 31, 2009 Fun puzzle. Where do you get so many puzzles, K Sengupta? I was going to ask him that, xamdam. Maybe KS is a reincarnation of Ramanujan Quote Link to comment Share on other sites More sharing options...
0 Guest Posted November 1, 2009 Report Share Posted November 1, 2009 (edited) Fun puzzle. Where do you get so many puzzles, K Sengupta? None of the said puzzles contributed to this site is an original. The various sources wherefrom these problems are gleaned happens to be so numerous that I have since stopped countin' 'em. Edited November 1, 2009 by K Sengupta Quote Link to comment Share on other sites More sharing options...
0 Guest Posted November 1, 2009 Report Share Posted November 1, 2009 Quote Link to comment Share on other sites More sharing options...
Question
Guest
F(x) denotes the absolute difference between SOD(x) and SOD(x+2), whenever x is a positive integer.
Determine the total number of distinct values of F(x) < 2000.
Note: SOD(x) denotes the sum of digits in the base ten representation of x.
Edited by K SenguptaLink to comment
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