A snowmobile has an initial velocity of +4.0?

A snowmobile has an initial velocity of +4.0
m/s.
a) If it accelerates at the rate of +0.40 m/s2
for 7.0 s, what is the final velocity?
Answer in units of m/s.
004 (part 2 of 2) 10.0 points
b) If instead it accelerates at the rate of -0.20
m/s2, how long will it take to reach a complete
stop?
Answer in units of s.