First write down all your known variables:
vi = 25m/s
a = 7.0m/s^2
t = 6.0s
vf = ?
Then choose the kinematic equation that relates all the variables and solve for the unknown variable:
vf = vi + at
vf = (25) + (7.0)(6.0)
vf = 67m/s
The final velocity of the motorcycle is 67m/s.
