Problem Solving

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

[spoiler]OA=E[/spoiler].

I am confused. Can any expert give me some help? Please. I'd be thankful.

Gmat_mission wrote: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

[spoiler]OA=E[/spoiler].

I am confused. Can any expert give me some help? Please. I'd be thankful.

For Group of n people k of whom are of the same GMAT, Index = (n-k)/n

For Group of 20 people 4 of whom are of the Female, Index = (20-4)/20 = 16/20 = 4/5 = 0.8

For Group of 20 people 16 of whom are of the Male, Index = (20-16)/20 = 4/20 = 1/5 = 0.2

Index of Female exceeds that of male = 0.8-0.2 = 0.6

Answer: Option E

I hope this helps!!!