masses $M_A$ and $M_B$ are related by $M_B=2M_A.$ Due to an interaction process, star A loses some of its mass,

$30$ that its radius is halved, while its spherical shape is retained, and its density remains $p_A.$ The entire mass

lost by $A$ is deposited as a thick spherical shell on $B$ with the density of the shell being ${}_A.$ If $v_A$ and $v_B$ are

the escape velocities from A and $B$ after the interaction process, the ratio $\frac{v_8}{v_A}=\sqrt[\phantom{2}]{\frac{10n}{{15}^{13}}}.$ The value of $n$ is