Answer:
2 m
Step-by-step explanation:
Let the child of mass 10 kg sits at a distance of d from axis on the side where the 15 kg child is sitting.
According to the principle of moments
Counter clockwise moments about O = clockwise moments about O
15 x g x 2 + 10 x d x g = 25 x g x 2
30 + 10 d = 50
d = 2 m
Thus, the 10 kg child should sit together with 15 kg at a distance of 2 m from the axis so that teh equilibrium is maintained.