Some Questions

Posted by E A Ibrahim on Apr 18, 2014; 3:32pm
URL: http://discussion-forum.276.s1.nabble.com/Some-Questions-tp7587363.html

1. The long-run cost function for each firm that supplies the output Y is given by C=Y^3-4Y^2+8Y. If aggregate demand for the output is given by Y=2000-100P, the equilibrium number of firms in a competitive industry will be equal to
(a) 100
(b) 200
(C) 500
(D) 800

2. If a consumer has a utility function U(x1, x2) = x1.x2^4. Then the fraction of income that he spends on x1 is
(A) 4/5
(B) 1/5
(C) 1/4
(D) Undeterminable. Requires additional information on prices

3. The rank of the matrix, H, is equal to
H= -3  6  2
      1  5  4
      4 -8  2
(A) 2
(B) 3
(C) 4
(D) 0

For the first two questions, I just want to verify whether my answer is correct or not. For the third question, I would like to know the way to solve it.