You stand by the railroad tracks as a train passes by. you hear a 1 000-hz frequency when the train approaches, which changes to 800 hz as it goes away. how fast is the train moving? the speed of sound in air is 340 m/s.

Aproduction line at v. j. sugumaran's machine shop has three stations. the first station can process a unit in 7 minutes. the second station has two identical machines, each of which can process a unit in 16 minutes (each unit only needs to be processed on one of the two machines). the third station can process a unit in 10 minutes. ▼ is the bottleneck station, with a bottleneck time of nothing minutes per unit (enter your response as a whole number).