1) A company offers long-distance telephone service to residential customers at a price of 8p per minute. At this price, the company sells 200 million minutes of calling per day. The company believes that its marginal cost per minute of calling is 5p. Based on a statistical study of calling patterns, the company estimates that it faces an elasticity of demand for long-distance calling by residential customers of -2.0. a) What is the company's marginal revenue? (10 marks) -please can u explain how it's derived thank you !

b) Based on your answer to a), should the company raise, lower, or leave unchanged its price? (10 marks)