joint cost curve

Posted by Target MA on May 31, 2013; 7:32am
URL: http://discussion-forum.276.s1.nabble.com/joint-cost-curve-tp7581525.html

You have two plants. Plant A has costs c(y) = y^2 and Plant B has costs c(y) = 2y^2. What is the
joint cost curve?
a) y^2 c) 5y^2/9
b) 2y^2 d) 3y^2