DSE-2010,question 57

Posted by sonudelhi on Jun 01, 2012; 1:27pm
URL: http://discussion-forum.276.s1.nabble.com/DSE-2010-question-57-tp7577429.html

57.a consumer has a utility function u(x,y)=xy suppose the consumer demands bundle (x,y).Now suppose sellers of good x offers a "buy one get  one free scheme.Given this scheme,consumer buys bundle (xd,yd) and get additional xd for free.which of the following statement must be true?
a.  xd>x and yd>y
b.  xd>x and yd=y
c.  Xd>x and yd<y
d.  xd=x and yd=y

how should i proceed?