An individual utility function is given by U(x,y) = x'y. Let U = 200, pX = $20 and py = $40. Consider this individual dual constrained expenditureminimization problem using the Lagrangian technique. The value of the Lagrange multiplier AD in this problem is [AD]. (NOTE: write your answer in number format, with 2 decimal places of precision level; do not write your answer as a fraction