1. Sally, a stockbroker has to decide whether to return to university to study for MBA. The MBA will take 3 years to complete. Following are the information that sally has: a) MBA fees will cost $20,000 per year b) her salary as a stockbroker is $80,000 per annum c) during her time studying she could work as a study helper at the university and earn $10,000 per year d) other costs of studying such as textbooks etc would cost $5000 a year e) her salary as a stockbroker would be $150,000 per annum with an MBA. What are the (yearly) opportunity costs of doing an MBA?.