An Impossible momentum problem?

[pokeefer]

Homework Statement

A 45 g steel marble collides obliquely with an identical stationary marble, and continues at 55 degrees to its original direction. The collision is perfectly elastic. What is the angle between the direction taken by the target ball and the original direction of the incident ball? (2 marks)

Homework Equations

Momentum = mass x velocity
Change in momentum = change in mass x velocity
Force = Change in momentum / Time

P1 + P2 = P1' + P2'
M1V1 + M2V2 = M1V1' + M2V2'

The Attempt at a Solution

Without knowing their velocities I find it really difficult to figure this question out.

 

[rock.freak667]

The Attempt at a Solution

Without knowing their velocities I find it really difficult to figure this question out.

First, before the collision, find the initial momenta in the x and y directions.

Then after the collision, find the momenta in the x and y directions.

Application of conservation of linear momentum will give you two equations.

You are told that they collide elastically, so what quantity is conserved here?