Solve the all parts of following question:
Question: A 45.0-kg girl is standing on a 169-kg plank. The plank, originally at rest, is free to slide on a frozen lake, which is a flat, frictionless surface. The girl begins to walk along the plank at a constant velocity of 1.35 m/s to the right relative to the plank. (Let the direction the girl is moving in be positive. Indicate the direction with the sign of your answer.)
Part A: What is her velocity relative to the surface of ice?
Part B: What is the velocity of the plank relative to the surface of ice?
I need help to find her velocity relative to the surface of ice.