Probability — practice question

The two ends of a pair of light inextensible strings, each of length $0.7\,\mathrm{m}$, are fixed to a particle $P$. Their other ends are fastened to two fixed points $A$ and $B$, which are in the same vertical line with $A$ higher than $B$. The particle $P$ undergoes horizontal circular motion with its centre at the midpoint of $AB$. Both strings make an angle of $60^\circ$ with the vertical. The tension in the string attached to $A$ is $6\,\mathrm{N}$ and the tension in the string attached to $B$ is $4\,\mathrm{N}$ (see diagram).