Answer:
V = ω R where ω is in radian
ω = V / R = 1200 ft / 20 ft = 60 radian
She has covered 60 radians
Check:
S = 60 rad / (2 π rad / rev) = 30 / π revolutions
1 rev = 2 π R = 40 π
N = 1200 ft / (40 π) = 30 / π rev
N = S / R = 1200 ft / (40 π ft) = 30 / π rev