this is a fairly subtle question.
if the bike was simply a 10kg object moving at 10m/s, then the KE would be KE = 0.5*m*v^2 = 0.5*(10kg)*(10m/s)^2 = 500 J
but there is also rotational KE in the motion of the tires, which depends on their moment of inertia and radius.
but as you didn't specify the details there, i guess we can just assume that the answer that you need is the solely the translational part, which is 500 J...
cheers