I'm too lazy to solve it but wow 12 seconds in 0.4 meters. that's way too slow to be pulling a sled and way too little friction for even ice. who comes up with high school phys probs.
ok since nobodys answered
A.)
D= 1/2T(V+Vo)
0.4=6(0+Vo)
0.4/6= Vo
Vo= .067 m/s
B.)
v-vo=at
-.0667=12a
a=...