Pleaseee physics help?

The brightest star visible from the northern hemisphere is the star Sirius, which is 8.7 light-years from Earth in the constellation of Canis Major. It takes a spaceship 4.9 years to travel from Earth to Sirius, according to the spaceship's on board clocks. According to Earth clocks, the trip takes 10,0 years. At what fraction of the speed of light did the spacecraft travel?