I want to know about the combination for sociology and Public Administration is it ok to take this combination!

Dear there,
 
I want to know about the combination for sociology and Public Administration is it ok to take this combination!
 
I am having very diverse back ground in my academics, bachelors in foreign language and than masters in management. so hardly got chance to study these subjects thoroughly,but still i m interested in these subjects. now i want to go for Civil Service, plz guide how to go ahead. 
 
keen to hear 
 
thank you
 
Raj