Jack and Leon, on a hot summer day, are fishing in their boat, when they make a decision to jump into the water to cool off. Jack having 45 kg jumps off the front of the boat having speed of 2 m/sec. While at the exact similar moment, Leon, 90-kg, jumps out of the back of the boat at a speed of 4 m/sec. When the boat consists of a mass of 100 kg and was at rest prior to the two boys jumping off, what will be the velocity just after both boys have abandoned ship?