A motorboat accelerates uniformly from a velocity of 6.5 m/s to the west to a velocity of 1.5 m/s to the west. If its acceleration was 2.7 m/s2 to the east, how far did it travel during the acceleration? I have to find: t, Vf, Vi, a, and Δx using one of the following formulas:
Vf = Vi + a*t
Vf2 = Vi2 + 2aΔx
Δx = ½(vf + vi)t
Δx= Vi*t + 1/2a*t^2

Which formula do I use? How do I solve this?

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?