An individual has preferences over two goods (X and Y ) from which they must choose. These preferences are represented by the utility function U = X^1/2 Y^1/2. The consumer is given an income of I, and faces prices PX and PY for the respective goods.

(a) List the exogenous and endogenous variables.

(b) The consumer's MRSX,Y = Y /X. Find this consumer's demand functions for X and Y.

(c) Find this individual's income elasticity of demand for good X ("X,I )