A marketing researcher at a computer company did a study examining user satisfaction with two operating systems.A total of 300 users were surveyed on the type of operating system used and their satisfaction with it.Use the following data set to answer questions 6-14: 
What is the probability that a user is satisfied with either system 9 or system 10?
Definitions:
Total Cost
Total cost is the complete cost of production that includes both fixed and variable costs.
Quantity
The amount or number of a material or immaterial good considered as a unit or total.
Average Total Cost
The total cost of producing a given output level divided by the quantity of output, indicating the average expense per unit produced.
Marginal Cost
The rise in financial outlay for the production of an extra unit of a product or service.
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