(3 marks) Sharifah has the following utility function:

2. (3 marks) Sharifah has the following utility function:U(X,Y) = √X + √Y where X is her consumption of brownies (pastry), with price PX=$1, and Y is her consumptionof espressos (coffee), with PY=$3. Assume that she has a budget I=$100.a. (2 marks) Using the method of Lagrange multipliers to derive Sharifah’s demand for brownies and espressos. How many brownies and espressos will Sharifah consume? (Partial quantities are possible.)b. (1 mark) What is the marginal utility of income?