Kinematics of Planets

Oct 2019
Hello everybody,
Three stars, each have size and mass of sun ( m=1,99*10^30 kg, R=6.96*10^8 m), they shape an equilateral triangle with side a= 5*10^12 m. If the three stars set simultaneously
free to move, what will be each velocity at the center of mass of the system?

Book's solution gives V=3.7*10^5 m/s. I found 4.4*10^5 m/s. Here is my solution:

Best regards!13.43.PNG