Which side will go down?

The force exerted by the father is his mass multiplied by the acceleration due to gravity ($g \approx 9.8 \, \text{m/s}^2$).

$$\text{Force}_A = \text{mass}_{\text{father}} \times g = 60 \, \text{kg} \times 9.8 \, \text{m/s}^2 = 588 \, \text{N}$$

The moment on side A is:

$$\text{Moment}_A = \text{Force}_A \times \text{distance}_A = 588 \, \text{N} \times 2 \, \text{m} = 1176 \, \text{Nm}$$

The force exerted by the daughter is her mass multiplied by the acceleration due to gravity.

$$\text{Force}_B = \text{mass}_{\text{daughter}} \times g = 25 \, \text{kg} \times 9.8 \, \text{m/s}^2 = 245 \, \text{N}$$

The moment on side B is:

$$\text{Moment}_B = \text{Force}_B \times \text{distance}_B = 245 \, \text{N} \times 5 \, \text{m} = 1225 \, \text{Nm}$$

$$\text{Moment}_A = 1176 \, \text{Nm}$$ $$\text{Moment}_B = 1225 \, \text{Nm}$$

Since $\text{Moment}_B > \text{Moment}_A$, the side with the greater moment will go down.

The side that will go down is:

$$\text{Side B}$$