Consider three galaxies, Alpha, Beta and Gamma. An astronomer in Beta sees each of the other two galaxies moving away from her in opposite directions at $0.70 \mathrm { c }$. At what speed would an observer in Alpha see the galaxy Beta moving?
A) $0.70 c$
B) $0.82 c$
C) $0.94 c$
D) $0.35 c$
E) $0.57 c$

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The Answer of Consider three galaxies, Alpha, Beta and Gamma. An astronomer in Beta sees each of the other two galaxies moving away from her in opposite directions at $0.70 \mathrm { c }$. At what speed would an observer in Alpha see the galaxy Beta moving?
A) $0.70 c$
B) $0.82 c$
C) $0.94 c$
D) $0.35 c$
E) $0.57 c$

Consider Three Galaxies, Alpha, Beta and Gamma 0.70c0.70 \mathrm { c }0.70c

Consider Three Galaxies, Alpha, Beta and Gamma $0.70 \mathrm { c }$