An economic consultant for X Corp. recently provided the firm's marketing manager with this estimate of the demand function for the firm's product:

Qx=120-5.0Px+2.0Py+0.25M+1.0Ax , where Qx represents the amount consumed of good X, Px is the price of good X, Py is the price of good Y, M is the income, and Ax represents the amount of advertising spent on good X. Suppose good X sells for Rs300 per unit, good Y sells for Rs250 per unit, the company utilises 2000 units of advertising and consumer income is Rs10000.

(a) Calculate the price elasticity, income elasticity, cross-elasticity and advertising elasticity of demand for good X and interpret your results.

(b) What is the marginal revenue?