Answer
See the detailed answer below.
Work Step by Step
First, we need to find the period of this pendulum which is given by
$$T=2\pi\sqrt{\dfrac{L}{g}}\tag 1$$
Now we need to find the number of full oscillations from 8 am to 12 pm which is 4 hours.
$$N=\dfrac{t}{T}$$
Plugging from (1);
$$N=\dfrac{t}{2\pi\sqrt{\dfrac{L}{g}}}$$
Plugging the known;
$$N=\dfrac{(4\times 3600)}{2\pi\sqrt{\dfrac{15}{9.8}}}$$
$$N=\color{red}{\bf1852}\;\rm oscillation$$
Now we need to find the amplitude after these 4 hours which is given by
$$A=A_0e^{-t/2\tau}$$
where $\tau=\dfrac{m}{b}$
$$A=1.5e^{-bt/2m}$$
Plugging the known;
$$A=1.5e^{\left[\frac{-(0.010)(4\times 3600)}{2(110)}\right]}$$
$$A=\color{red}{\bf0.78}\;\rm m$$
