2 Galaxies, Special Relativity, 4 Possible Alternatives

Galaxy A is moving away from Earth with a speed of 0.45 c. Galaxy B, located in the diametrically opposite direction, is moving away from us with the same speed. What multiple of c corresponds to the rate of recession measured by an observer from galaxy A to galaxy B?

a) +0,95 c

b) 1,16 c

c) -0,622 c

d) -0,689 c

Sample Solution