Refer to the diagram shown below.
m = the mass of the truck
N = normal reaction
g = 9.8 m/s²
μ = 0.2, the coefficient of kinetic friction
The resistive force on the truck is
F = μN = μmg = 0.2*(9.8)m = 1.96m N
The acceleration (actually deceleration) is
a = F/m = -1.96 m/s²
Let d = distance for the truck to come to rest from an initial velocity of u = 35 m/s.
Then
u² + 2ad = 0
(35 m/s)² + 2(-1.96 m/s²)(d m) = 0
d = 35²/3.92 = 312.5 m
Answer: 312.5 m
