Midpoint formula
mid of (x1,y1) and (x2,y2) is

so
(22,15)=

therefor
22=

and
15=

slv each
22=

times both sides by 2
44=18+x1
minus 18 both sides
26=x1
15=

times both sides by 2
30=6+y1
minus 6
24=y1
the other point is (26,24)
A&C
B&F
Try it by fold the prism with paper
I don't know if I understand what you're saying but the likelihood of the event is as you already stated... 1/4, or I guess 25% so in other words a one in four chance of taking the bus home.
1. figure name triangular prism
bases 4
faces 4
edges 6
verticies 4
skew lines idk sorry
2. figure name hexagonal based triangular prism
bases 1
faces 7
edges 12
verticies 7
skew lines sorry idk
for skew lines, this might help