1. The problem statement, all variables and given/known data If the relative velocity of object B to object A is 10 m/s, and the relative velocity of object C to object B is 10 m/s, what is the relative velocity of object C to object A? 2. Relevant equations These should be vectors just to give a heads up vbs= vbw+vws vba=vab These are the equations given in my book 3. The attempt at a solution My first attempt was using the second eqaution since the question before it was similar but it did not have c and I used the second formula and I got it right. The second formula uses the idea of reference frames. So A and B have the same magnitude but different direction. So B and C is the same. So -10m/s -10m/s= -20 m/s. I was given this option and was told it was wrong. Then I made it an absolute value and it was wrong. So would it be -10m/s + 10m/s. Because if B is -10m/s, the opposite magnitude would be 10m/s and adding them together would give me 10? Or would I need more information to solve this.