[4] The publisher of an economics textbook sells its book to consumers in the United Kingdom (UK) and the United States (US). Currently, the publisher charges a price equivalent to $100 in each country. However, after hiring an analyst, who estimates the price elasticity of demand for the book in the US is equal to - 0.50, while in the UK it is equal to - 1.50, if the publisher wishes to maximize its total revenue from the book, carefully explain what it should do to the prices charged in each country (i.e., should prices remain at $100, or be changed, and why?).