v=u+at
where
v is the final velocity
u is the initial velocity
a is the acceleration
t is the time
From the question
u = 10 m/s
a = 6 m/s²
t = 20 s
Substitute the values into the above formula and solve
That's
v = 10 + 6(20)
= 10 + 120
We have the final answer as
130 m/s