How Fast Does My Friend Appear When We Travel in Opposite Directions at 0.7c?

[Shark 774]

If I travel away from Earth at 0.7c, relative to the Earth and my friend travels in the opposite direction at 0.7c, relative to the Earth, what speed to I measure him to be traveling at, relative to myself?

 

[DrGreg]

$$\frac{0.7 + 0.7}{1 + 0.7 \times 0.7}\,c$$

Velocity-addition formula