Allegiant airlines charges a mean base fare of $88. in addition, the airline charges for making a reservation on its website, checking bags, and inflight beverages. these additional charges average $37 per passenger. suppose a random sample of 50 passengers is taken to determine the total cost of their flight on allegiant airlines. the population standard deviation of total flight cost is known to be $39

a. allegiant airline reports a population mean base fare of $89 and a population mean additional fare of $39 per person. what is the population mean cost per flight?
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b. what is the probability the sample mean will be within $10 of the population mean cost per flight (to 4 decimals)?
c. what is the probability the sample mean will be within $5 of the population mean cost per flight (to 4 decimals)?