28. (2 points) A cross-country athlete can currently run the 5k (5 kilometer race) in 22 minutes. What does her average speed need to be to run the race to meet her goal of
18 minutes? Show your reasoning. Answer in km/min. s =

Consider a production line with five stations. station 1 can produce a unit in 9 minutes. station 2 can produce a unit in 10 minutes. station 3 has two identical machines, each of which can process a unit in 12 minutes (each unit only needs to be processed on one of the two machines. station 4 can produce a unit in 5 minutes. station 5 can produce a unit in 8 minutes. which station is the bottleneck station?