it takes a delta to form 100 years or more
It is 2400/850 = 48/17.
They are number of the form 850*k where k is any integer.
850 = (8 x 100) + (5 x 10) + (0 x 1)
It can take 850 years for 2cm of soil to form
850
8/50 = 4/25
850
0.0824
Feudalism first appeared in its complete form in approximately 850 A.D.
0.9444
85/100 or 17/20 inches.