Giving brainliest also gonna need an Explanation on how to get the answer with the Answer

Little’s law firm has just one lawyer. customers arrive randomly at an average rate of 6 per 8 hour workday. service times have a mean of 50 minutes and a standard deviation of 20 minutes. how long does a customer spend at little’s law firm on average?

Ineed me i stuck and i don’t want to get it wrong

Solve each quadratic equation by factoring and using the zero product property. 14x - 49 = x^2