A speedboat starts from rest and accelerates at +1.69 m/s2 for 7.18 s. At the end of this time, the boat continues for an additional 4.55 s with an acceleration of +0.468 m/s2. Following this, the boat accelerates at -0.657 m/s2 for 8.38 s. (a) What is the velocity of the boat at t = 20.11 s? (b) Find the total displacement of the boat.