Problem Solving

Hi,

I thought the answer is C) but correct answer turned out to be E)...

14. For a group of n people, k of whom are of the same GMAT, the n-k/n expression yields an index for a certain phenomenon in group dynamics for members of that GMAT. For a group that consists of 20 people, 4 of whom are females, by how much does the index for the females exceed the index for the males in the group?
(A) 0.05
(B) 0.0625
(C) 0.2
(D) 0.25
(E) 0.6

Female index - male index
= (20-4)/20 - (20-16)/20
= 12/20
= 0.6

female index = (20-4)/20 = 16/20 = .8
male index = (20-16)/20 = 4/20 = .2
So difference = .8-.2=.6

hope this sound more easier!!

20

4f 16m

1/5 4/5 --> phenomenon

increase = (4/5 - 1/5)/(1/5) = 3/5 =0.6

This has been discussed in an earlier thread...However, here goes

Important thing is index of "k" = n-k/n and not k/n
Hence index of females = 20-4/20 = 16/20 = 4/5
Index of males = 20-16/20 = 4/20 = 1/5
Index of females - Index of males = 4/5 - 1/5 = 3/5 = .6