Find the height of a triangle whose base is 40 cm and area is 0.1 metre²

Ineed with number 17 i don’t get it at alll

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?

Collin did the work to see if 10 is a solution to the equation r/4=2.4