Two boats 310 masses m1 = m2 = kg and 160 kg are parallel courses with velocities V1 and V2. When boats are close from each other in the boat shifted bag mass m = 25 kg, then the boat continues to move parallel courses, but with velocities U1 = -1,7 m / s and U2 = 2,8 m / s. Find speed V1.

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