infinityzero Posted January 2, 2006 Share Posted January 2, 2006 Is there a way to do this problem using logic and avoiding calculations, especially when running out of time? It'd be much appreciated. Thanks. The 1992 census found that city A had 18% fewer residents than city B. The 1994 census found that city A's population grew by 18% over 1992, while city B's population had remained the same. Col A: population of city A in 1994 Col B: population of city B in 1994 Ans: B Quote Link to comment Share on other sites More sharing options...
comp Posted January 2, 2006 Share Posted January 2, 2006 hi infinity0, for this problem u have to calculate but u can make it easy by taking figures which will make your calculation fast n easy Quote Link to comment Share on other sites More sharing options...
hace Posted January 2, 2006 Share Posted January 2, 2006 u dont need to calculate since in 1992 pop. of B is higher A is lower to reach B's pop A's pop. should increase more than %18 this is because if B's pop is 100 A's is 82 18% of 100 is 18 but 18% of 82 is lesser so A's pop in 1994 is not 100 so the answer is B Quote Link to comment Share on other sites More sharing options...
comp Posted January 2, 2006 Share Posted January 2, 2006 yes hace u got a way out for this problem Quote Link to comment Share on other sites More sharing options...
krishnakanthc Posted January 2, 2006 Share Posted January 2, 2006 I believe you should put the problem down into equations. That should make such problems easier. Youll never get it, if you try to imagine the answer. Otherwise, it was an easy problem. Quote Link to comment Share on other sites More sharing options...
comp Posted January 3, 2006 Share Posted January 3, 2006 If 72.42 = k(24+n/100) where k and n are positive integers and n 17 16 15 14 13 another problem: Y X 7 + 6 Y = Y 7 X In the sum above ,if X and Y each denote one of the digits from 0 to 9 inclusive then X = 9 5 2 3 1 0 Quote Link to comment Share on other sites More sharing options...
hace Posted January 3, 2006 Share Posted January 3, 2006 If 72.42 = k(24+n/100) where k and n are positive integers and n 17 16 15 14 13 another problem: Y X 7 + 6 Y = Y 7 X In the sum above ,if X and Y each denote one of the digits from 0 to 9 inclusive then X = 9 5 2 3 1 0 7242=2400k+kn k=3 kn=42 n=14 k+n=17 YX7 +6Y --- Y7X x=0 y=3 107 +63 --- 170 Quote Link to comment Share on other sites More sharing options...
comp Posted January 3, 2006 Share Posted January 3, 2006 how u solved this problem ? Please explain. Another question about ur solution : ur sum shd be 370 instead of 170 as ur taking y =3 ? 7242=2400k+kn k=3 kn=42 n=14 k+n=17 YX7 +6Y --- Y7X x=0 y=3 107 +63 --- 170 Quote Link to comment Share on other sites More sharing options...
hace Posted January 3, 2006 Share Posted January 3, 2006 how u solved this problem ? Please explain. Another question about ur solution : ur sum shd be 370 instead of 170 as ur taking y =3 ? sorry you r right first clue is that there is no carry from tens to hundreds if we look only tens X 6 - 7 i thought at first X can be 1 if it is 1 then if we look at unit digits 7 Y - 1 so Y is either -6 or 4 but if it is 4 then there is a carry so the whole calculation is wrong then I thought let X be zero I didnt tried numbers greater than 1 since if I had used it the same scenario occurs as it occured with X=1 so X=0 by looking tens X 6 - 7 since X=0 there should be a carry from unit digits 7 Y - 0 so Y can be -7 or 3 so naturally it is 3 then the sum becomes 10 one carry occurs it adds to tens then th whole calculation is correct Quote Link to comment Share on other sites More sharing options...
comp Posted January 3, 2006 Share Posted January 3, 2006 Thanks a lot , hace sorry you r right first clue is that there is no carry from tens to hundreds if we look only tens X 6 - 7 i thought at first X can be 1 if it is 1 then if we look at unit digits 7 Y - 1 so Y is either -6 or 4 but if it is 4 then there is a carry so the whole calculation is wrong then I thought let X be zero I didnt tried numbers greater than 1 since if I had used it the same scenario occurs as it occured with X=1 so X=0 by looking tens X 6 - 7 since X=0 there should be a carry from unit digits 7 Y - 0 so Y can be -7 or 3 so naturally it is 3 then the sum becomes 10 one carry occurs it adds to tens then th whole calculation is correct Quote Link to comment Share on other sites More sharing options...
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