## Homework Statement

Faraway Point starbase launches a probe toward the starships approaching from the same direction. The probe has a velocity relative to the Picard of -0.895c. The Picard approaches starbase Faraway Point with a speed of 0.795c, and the La Forge approaches the starbase with a speed of 0.895c.

A) What is the velocity of the probe relative to the La Forge?
B) What is the velocity of the probe relative to Faraway Point starbase?

## Homework Equations

v23=(v21+v13)/(1+(v21+v13)/c^2)

## The Attempt at a Solution

Okay, this stuff really confuses me. I don't even know how to label them because there are four entities in the problem, but this equation only allows for three. Also, I'm not sure what the velocities of the Picard and the La Forge are relative to (I think to the Faraway Point?) Either way, I need a little help getting on the right path with this then hopefully I can take it from there.

I'm also not that great at the algebra of moving around the equation, but I may be able to handle that.

$$V_{a/c} = \frac{V_{a/b} + V_{b/c}}{1 + (V_{a/b} V_{b/c})/c^2}$$