Uhhh... Thought rule of thumb for a VDP was divide HAT by 3 which yeilds your distance from the runway to begin your descent... The 6x airspeed/3x altitude to use is more for enroute descent planning. And it should be 6x ground speed. I use the 6x ground speed/3x altitude to lose rule in the ERJ and it works pretty much every time.

And don't take my word for the airplane they pick. It's been almost a year since I interviewed and things might have changed. However, knowing the way the company operates and how they interview, I don't think they'd sucker punch you and ask questions about an airplane you've got just a few hours in.