What is magnitude of the momentum

Question

A student standing on a stationary skateboard tosses a textbook with a mass of mb = 1.55 kg to friend standing in front of him. The student and skateboard have a combined mass of mc = 95 kg and the book leaves his hand at a velocity of 3.69 m/s at an angle of 34° with respect to the horizontal. 

Randomized Variables

mb = 1.55 kg

mc = 95 kg

vb = 3.69 m/s

θ = 34°

Part (a) write down an expression for the magnitude of the velocity of the student, vs, after throwing the book.

Part (b) Calculate for magnitude of the velocity of the student, vs in m/s?
vs = 

Part (c)  What is magnitude of the momentum, Pe, which was transferred from a skateboard to the Earth during the time the book is being thrown (in kg-m/s)?