If the car starts from rest, how long would it take for it to move 20cm

An initially resting 300g car is dragged along a horizontal frictionless table by massless cord. The cord is attached to a vertically hanging 60g mass by a frictionless massless pulley. If the car starts from rest, how long would it take for it to move 20cm?

F=ma

Car:
F=(0.3kg)a=T-Friction
Friction=0
T=(0.3kg)a

Mass:
F=(0.06kg)a=T-W
W=mass(gravity)
(0.06kg)a=T -( 0.06kg)(9.81m/s^2)
T=(0.06kg)a+(0.06kg)(9.81m/s^2)

(0.3kg)a = (0.06kg)a+(0.06kg)(9.81m/s^2)
(0.3kg)a-(0.06kg)a = (0.06kg)(9.81m/s^2)
a(0.3kg-0.06kg) = (0.06kg)(9.81m/s^2)
a = [(0.06kg)(9.81m/s^2)] / [(0.3kg-0.06kg)]
a = 1.635m/s^2

s = 0.5at^2
t = √ s / (0.5a)
t = √ (0.2m) / (0.5x1.635m/s^2)

t = 0.4946s