The answer to this question is 0.4
We know that they have:
2 entrences
3 ways to chose (escalator,elevator and stairs)
8 gates
and again 3 ways to chose (escalator, elevator and stairway)
now you have to multiply it:

There are 144 different ways that Anita and Terry can go from street level to the trains:)
11 and 12
7 and 512
12 and 10
0 and 78
left side numerator
right side denominator
All you have to is divide two consecutive terms to calculate the common ratio
1/4 divided by 5/12 = 1/4 * 12/5 = 12/20 = 3/5
Volume of one cubic block = (1/6)^3 = 1/216 cu ins
Volume of the prism = 1/3 * 2/3 * 2/3 = 4/27 cu ins
Number of blocks to fill prism = 4/27 / 1/216 = (216*4) / 27 = 32