Physics Question. Could anyone show me how to solve it?

Question

A motorcycle is moving at 31 m/s when the rider applies the brakes, giving the motorcycle a constant deceleration. During the 5.0 s interval immediately after braking begins, the speed decreases to 15 m/s. What distance does the motorcycle travel from the instant braking begins until it comes to rest?

Answer 1

acceleration=Δ/time=(15-31)/5=-3.2m/s*s

distance=Vinit*t+.5a*t*t=31*5+.5*3.2*5... m