You are the manager of a firm that receives revenues of $30,000 per year from product X

Question:

You are the manager of a firm that receives revenues of $30,000 per year from product X and $70,000 per year from product Y. The own price elasticity of demand for product X is –2.5, and the cross-price elasticity of demand between product Y and X is 1.1. How much will your firm’s total revenues (revenues from both products) change if you increase the price of good X by 1 percent?