Student A of mass 40kg and Student B of mass 60kg stand on identical, friction-free roller skates. Starting from rest, they push each other apart. After the push, Student A moves east with a speed of 1.5m/s. What is the speed and direction of Student B immediately after the push?
a) 1.22m/s toward the west
b) 1.0m/s toward the west
c) 2.25m/s toward the west
d) 1.0m/s toward the east