Let the number of degrees that the counterclockwise particles moves through be d degrees.
The number of degrees that the clockwise particle moves through will be 360-d degrees:. The times taken to where they meet is the same for both particles.
Rate = degrees / time , so:-
3 = d/ t ; giving t = d/3
42 = 360- d / t so t = (360 - d) / 42
Equating values of t:-
d/3 = (360-d) / 42
42d = 1080 - 3d
d = 1080 / 45
= 24 degrees (answer)
