In article .com,
"Jay Honeck" wrote:

I know, but it's the kind of simple math that I *should* be able to do
in my head.

Cruise altitude - target altitude = altitude loss

9,500 - 2,000 = 7,500

altitude loss/500fpm = minutes or [altitude loss/1,000] x 2

7,500/500 = 15 minutes or 7.5 x 2 = 15 minutes

minutes x miles per minute = miles

15 x 1.5 = 22.5nm 15 x 2 = 30nm 15 x 2.5 = 37.5nm 15 x 3 = 45nm

90 kts = 1.5 nm/m
120 kts = 2.0 nm/m
150 kts = 2.5 nm/m
180 kts = 3.0 nm/m