Centre of Mass and Collision Part 1

Given,
The mass of the first ball, m1=10kg The mass of the second ball, m2=20kg
The initial velocity of the first ball, u1=10√3m/s
The initial velocity of the second ball, u2=0m/s
The final velocity of the first ball, v1=0m/s
The final velocity of the first piece of the second ball, v2=10m/s
Let's consider the final velocity of the second piece of the second ball =v2
As shown in the figure,
The net external force on the system is to be zero. Hence, we can use the law of conservation of linear momentum in both directions. ln‌x-direction the linear momentum conserved,
In x-direction the linear momentum conserved,
⇒‌‌v3=20m/s
Hence, the velocity of the ball moving at 30∘ with respect to the X-axis is 20m/s.
So, the value of x to the nearest integer is 20 .