[ElectroMaster88]

I need to figure out with which molecule out of these two (A or B), NaOH will react faster in a SN2 mechanism.
I've been told that "In general, for SN2 chemistry, nucleophiles may only attack an electrophilic chair when the leaving group is in an axial position", but when I draw the chair conformations, the position of the Br changes depending on if the chair is flipped or not.
I don't know what to do with it.

[Babcock_Hall]

You wrote "the position of the Br changes..."  Can you explain in detail what you mean?  I have an idea, but I want to make sure that we are on the same page.