Momentum of the bullet and block before impact = 50 x 10-3 x 300 = 15 Ns
If v the velocity of a system (bullet and block) after collision, then by the conservation law of momentum, 15 = (10 + 0.05)v
or, v = {15}/{10.05} = 300/201 ms-1
and the height raised by the system,
h = v2/2g = {(300/201)2}/{2 x 9.8} = 0.1136 m