Is Janice using marginal cost and marginal revenue correctly in her analysis?  Explain the errors in her analysis, if any

 Calculate the break even number of additional customers for each added hour of operation up to 4am.

Calculate the break even number of additional customers for an entire year,     assuming (i) a closing time of 4am and then (ii) your recommended closing time, if   it differs from 4am.

Find the safety margin on new customers for the year.  [Hint:  For the per-year analysis, remember to account for the cost of the security upgrade.  Use straight- line depreciation as a measure of the fixed cost of the security upgrade, and then

Add the cost of overtime labor for the additional hours of business for each of the         360 business days in the year.]