Descent is planned from 7500 ft AMSL
so as to arrive at 1000 ft AMSL 6 NM from a VORTAC.
With a GS of 156 kts and a rate of
descent of 800 ft/min. The distance from the VORTAC when descent is started is:
You must descend 6500ft (7500ft to
1000ft) at 800ft/min … so in terms of TIME, it will take: 6500/800 = 8.125 mins
Your G/S is 156kts … distance
travelled = 156 x 8.125/60 = 21.1nm
So you must start the descent 21.1 +
6 = 27.1nm from the VORTAC