CrackXam Posted September 4, 2007 Share Posted September 4, 2007 Of the students in the class, 55% of the females and 35% of the males passed the exam. Did more than half the students pass the exam? 1) More than half the students in the class are females 2) The number of female students is 20 more than the the number of male students. OA - E IMO - B Quote Link to comment Share on other sites More sharing options...
lsr Posted September 4, 2007 Share Posted September 4, 2007 I agree with the OA. CrackXam, how can you solve the question with the second statement? Quote Link to comment Share on other sites More sharing options...
givemeanid Posted September 4, 2007 Share Posted September 4, 2007 E for me Quote Link to comment Share on other sites More sharing options...
CrackXam Posted September 5, 2007 Author Share Posted September 5, 2007 Supp there are 100 students, 60 F and 40 M. 55% of 60 +35%of 40 suppose there are 140 students, 80F and 60 M 55% of 80 +35% of 60 In all cases it ill be lesser than 1/2! Quote Link to comment Share on other sites More sharing options...
lsr Posted September 5, 2007 Share Posted September 5, 2007 Supp there are 100 students, 60 F and 40 M. 55% of 60 +35%of 40 suppose there are 140 students, 80F and 60 M 55% of 80 +35% of 60 In all cases it ill be lesser than 1/2! You are absolutely right!!! (I totaly missed it....) From the question stem: 55%F = (55/100)F = (11/20)F therefore F=20f; where f is a positivie integer. 35%M = (35/100)M = (7/20)M therefore M=20m; where m is a positive integer. Is (55%F+35%M)/(F+M)>1/2? which simplyfies to: F>3M? First Statement: F>M not sufficient. Second Statement: F=M+20 subtitute into the question stem, M+20>3M ? M since M=20m, and m is a positive integer. the smallest value of M is 20. Therefore Sufficient. Answer is B. GOOD CATCH CrackXam!!![banana] Quote Link to comment Share on other sites More sharing options...
DJValentino Posted October 20, 2007 Share Posted October 20, 2007 Good question CrackXam!! Quote Link to comment Share on other sites More sharing options...
ibo Posted October 20, 2007 Share Posted October 20, 2007 My answer is E too Quote Link to comment Share on other sites More sharing options...
Gmater-1 Posted December 20, 2008 Share Posted December 20, 2008 Can anybody help me in understanding LSR's explanation? tnx Quote Link to comment Share on other sites More sharing options...
cesar82 Posted December 20, 2008 Share Posted December 20, 2008 I dont know if this will help you in understanding, but this is one way of looking at it (fast) if at all, the second statement would be insufficient at lower values of boys and girls. at higher values, like 100, 1000 boys etc.. the respective percentages wont add up to 50% of the total at the least possible value which is 20 boys (35% * 20 has to be an integer) we still have so it would seem that b is sufficient Quote Link to comment Share on other sites More sharing options...
bose Posted December 22, 2008 Share Posted December 22, 2008 deleted Quote Link to comment Share on other sites More sharing options...
sunirs Posted December 24, 2008 Share Posted December 24, 2008 Ans is b as it is already explained by lsr Quote Link to comment Share on other sites More sharing options...
Belka Posted March 5, 2012 Share Posted March 5, 2012 Let M - number of males, F - number of females Need to compare (M+F)/2 and 0,55F+0,35M given that F = M+20 (M + M + 20)/2 compare with 0,55(M +20) + 0,35M (2M+20)/2 compare with 0,55M+0,35M+11 M+10 Quote Link to comment Share on other sites More sharing options...
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