Forces and equilibrium — practice question

A particle weighing $25\text{ N}$ has two light inextensible strings fixed to it. Each string goes over a smooth fixed pulley and then supports a hanging particle of weight $A\text{ N}$ or $B\text{ N}$ at the lower end. The parts of the strings that slope away make angles of $30^\circ$ and $40^\circ$ respectively with the vertical (see diagram). The system is in equilibrium.