5. Suppose Lan's utility function is UL(x,y)
=xL5yL9 and Dan's
utility function is UD(x,y)
=xD7yD3, where
xi and yi denote respectively the
amount of good X and of good Y consumed by person i, i=L, D.
A total of 31 of each good is available and it is to be divided
efficiently between Lan and Dan. How many units of
good X should Lan get if we give Dan 13
units of good Y such that the allocation
is efficient?
Enter the amount of
good X below.