Weight = k/(distance)². Let's find the value of k when distance = earth radius:
180 = k/(3900)² → k = 180 x 3900² → k = 2,737,800,000
If he is at 325 miles ABOVE the earth, the distance becomes: 3,900+325=4,225 miles and his weight becomes:
Weight = k/(distance)² → Weight = 2,737,800,000/(4225)² = 153.37
Weight = 153.37 lb