consumer behaviour

Posted by poulami on Jan 18, 2012; 11:37am
URL: http://discussion-forum.276.s1.nabble.com/consumer-behaviour-tp7199859.html

suppose a consumer's utility function for three goods is separable that is u(x1,x2,x3)=f1(x1)+f2(x2)+f3(x3) where each fi is increasing and strictly concave,i=1,2,3.show that
none of the goods are inferior.
Sir if you please give the solution to this problem...