The damping time constant is m/b = 11000s
n t2 = 4*3600 sqrt((9.8/15) - (0.01^2/4*110^2) / 2π = 1852.5
You need to square root ((9.8/15) - (0.01^2/4*110^2) / 2π in order to get the final answer or to get how many oscillation will the pendulum have completed.
So the answer in this question is 1852.5 and decimals are considered as an integer.
