standard_description: Find the inverse of a matrix if it exists and use it to solve systems of linear equations (using technology for matrices of dimension 3 × 3 or greater).
problem_activity: Task
Bob’s Bagel Shop has estimated the following probabilities for the number of bagels a randomly-selected customer buys when he or she enters the shop.
{"table": [{"_attributes": {"class": ["centered", "narrow"]}, "tbody": [{"tr": [{"th": [{"_value": "No. of Bagels"}, {"_value": "Probability"}]}, {"td": [{"_value": "1"}, {"_value": ".5"}]}, {"td": [{"_value": "2"}, {"_value": ".1"}]}, {"td": [{"_value": "3"}, {"_value": ".1"}]}, {"td": [{"_value": "6"}, {"_value": ".1"}]}, {"td": [{"_value": "12"}, {"_value": ".2"}]}]}]}]}
Bob sells bagels for \$0.80 each, or \$9.00 for a dozen. If $X =$ the amount of money Bob collects from a randomly-selected customer, find and interpret the expected value of $X$.


aligns: no