I like using the units and
120Nautical Miles (nm) per 1 hour = 120nm/ 1hr
or 120nm / 60minutes(min) which equals 2nm / 1min
Required climb gradient for the Pitkin four out of KASE = 500ft/1nm
ft/min required = 2nm/1min * 500ft/nm
=
2nm * 500ft
------------
1min * 1nm

equals 1000ft/1min
note the nm cancel out and you're left with ft/min as your units.

Of course you're flying a part 25 aircraft and ahh screw it, if we lose one we'll just go visual down to Rifle. . .