Answer:
The period of the system of ladder and woman, T = 2.5 seconds
Step-by-step explanation:
Mass of the ladder,

Mass of the artiste,

Length of the ladder, L = 42.0 kg
The total moment of inertia can be calculated using the equation:

D = L/2 = 3/2
D = 1.5 m
The frequency of the system of ladder and woman follows that of a physical pendulum which can be given by the equation:

The period of the system of ladder and woman is given by:
T = 1/f
T = 1/0.4
T = 2.5 seconds