Lorentz particles

Charged particles A and B are entered vertically into a uniform magnetic field as the arrow at the bottom of the box indicates. Their respective traces of movement are the two green half circles. Particles A and B have the same mass, and the radii of their traces are $$2R$$ and $$R,$$ respectively. What are the electrical signs of the two particles? And, if the quantity of the electric charge of A is $$q,$$ then what is the quantity of the electric charge of B?

The direction of the magnetic field is downward through the plane.

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