dse 2009 q35

[SHIKHA]

a company has 100 employees , 40men and 60 women . there are 6 male executives. how many female executive should there be for gender and rank to be independent???
a) 9
b)6
c)10
d)8

[anon_econ]

We must have
P(male intersection executive)=P(male).P(executive)
6/100=40/100*(6+x)/100, where x is the no of female executives.

[ritu]

9????

[SHIKHA]

thanks..bt     ..."for gender and rank to be independent" ...what does dis mean???
@ritu yes

[s]

it means the events Male/Female and Executive/Non executive are independent. that is how it can be written P(male intersection executive)=P(male).P(executive)