Similar triangles?? Proportions

Hello everyone,
I tried to solve part a) of this question using similar triangles and their proportion, but it didn't work.
Also, in part b) isn't the ratio supposed to be 1:1 ?(same distance between basement - ground, and ground - first floor)

Thank you

 

Where are you seeing similar triangles?

Also, while we cannot assume that the drawing is "to scale", there is nothing in the exercise that suggests that the height differences between the basement, the ground floor, and the first floor are all the same.

(The drawing doesn't have all points labelled. For ease of communication, let's say that the point where Alison started is point A, the point where Briana started is point B, the point where the one escalator meets the ground floor is point G, and the point where the other escalator meets the first floor is point F.)

Edit: We can also add the point K (forming a square), as was provided to you elsewhere.