Answer
See the detailed answer below.
Work Step by Step
a) Let's assume that the height of one floor is 3 meters. So, the height of the first floor is $y_1=3$ m and the height of the second floor is $y_2=6$ m.
$$\Delta y=6\;\rm m$$
b) Let's assume that the number of steps of the stairs for one floor is 25 steps and that one step would take one second.
Thus, it takes 25 seconds to run up one floor. And hence, it takes 50 seconds to run up these two flights of stairs.
$$\Delta t=50\;\rm s$$
c) Now we need to find the power in watts.
We know that power is given by
$$P=\dfrac{W}{\Delta t}$$
where $W$ is the work done by you to move 6 meters upward. And the work is given by $W=\Delta U_g=mg\Delta y $
$$P=\dfrac{mg\Delta y}{\Delta t}$$
where $m$ is your mass which we can assume to be 80 kg.
Thus,
$$P=\dfrac{80\times 9.8\times 6 }{50}=\color{red}{\bf 94.1}\;\rm W$$
And the power in horsepower (hp) is given by $\rm 1 \;hp=746 \;W$
$$P=\dfrac{94.1 }{ 746}=\color{red}{\bf 0.13}\;\rm hp$$
