CAN A PHYSICIST PLEASE HELP WITH THIS QUESTION!? (Conservation of momentum)?

Original momenta, 0.15 - 0.10 = 0.05 kg-m/sec. Final momentum A = 0.3 x -0.2 = -0.06; A + B = +0.05 (conservation); B = 0.11 = mv; v = 0.11/0.2 = 0.55. Looks to me as though you got it right. Previous response has not taken directions into account.