Answer:
25.12 seconds
Explanation:
As we have been given ion the question,
Tangential speed of her brother at the Wooden Horse = 6 m/s
Tangential speed of Sheila = 4 m/s
Radius of merry go round, r = 8 m
Now,
We know that,
v = r.ω
So,
Angular velocity of brother is given by,

And,
Angular velocity of Sheila is given by,

Relative Angular Velocity = 0.75 - 0.5 = 0.25 rad/s.
Therefore, the time taken by Sheila to encounter her brother again is given by,

Therefore, Time Taken to encounter again is 25.12 seconds.