Problem $14\mathrm{.}015-$ The position of fragment

A $13-$kg projectile is passing through the origin $O$ with a velocity $v_O=(35\frac{m}{s})i$ when it explodes into two fragments A and $B,$ of mass $5$ kg and $8$ kg $,$ respectively. Knowing that $3$ s later the position of fragment $A$ is $(90m,7m,-14m),$ determine the position of fragment $B$ at the same instant. Assume $a_y=-g=-9\mathrm{.}81\frac{m}{s^2}$ and neglect air resistance. $($Include a minus sign if necessary.$)$

The position of fragment $B$ is $r_B=1m$ m$)$j $+($ m$)k.$