A 100 Kg Mass, Initially at Rest, Is Blown Apart

Multiple Choice

A 100 kg mass, initially at rest, is blown apart into a 60 kg piece and a 40 kg piece. After the blast, the two masses are moving apart with a relative velocity of 60 m/s. The speed of the 60 kg mass is

A) 88 m/s.
B) 67 m/s.
C) 51 m/s.
D) 40 m/s.
E) 24 m/s.