How Does the Second Fragment's Velocity Change After a 2D Explosion?

[satasonic]

Homework Statement

A 4.00-kg cannon ball is flying at 18.5 m/s
[0º] when it explodes into two fragments.
One 2.37-kg fragment (A) goes off at
19.7 m/s [325º]. What will be the velocity of
the second fragment (B) immediately after
the explosion? Assume that no mass is lost
during the explosion, and that the motion
of the fragments lies in the xy plane.

Homework Equations

p = mv

The Attempt at a Solution

K so i got my graph drawn, but because this is an explosion i have no idea how to set up the x and y equations, any help?

 

[rl.bhat]

You have to apply the conservation momentum. The explosion does not make any difference.
Resolve the momentum Pa and Pb along x and y axis. And proceed.