A bomb at rest explodes into three fragments. Two of these fragments with mass m₁ = 2 kg, and m₂ = 1 kg respectively, travel in left direction; the other fragment with mass m₃ = 3 kg travels in opposite direction. If the velocities of fragments 1 and 2 are v₁ = 5 m/s and v₂ = 2 m/s respectively, find the velocity of fragment 3.