Mass of each black hole M = 10 solar masses = 2 x 10^(31) kg Radius of black holes RBH = 30 km Radius of orbit R = 2 RBH = 60 km Velocity in orbit v = 0.75 x 10^(8) m/s = 0.25 c Distance from Earth D = 340 Mpc = 1 x 10^(25) m