Question 69
There are two buildings facing each other, each $5$ stories high. How many ways can Kevin string ziplines between the buildings so that:
a. each zipline starts and ends in the middle of a floor.
b. ziplines can go up, stay flat, or go down, but can't touch each other (this includes touching at their endpoints).
Note that you can't string a zipline between two floors of the same building.
a. each zipline starts and ends in the middle of a floor.
b. ziplines can go up, stay flat, or go down, but can't touch each other (this includes touching at their endpoints).
Note that you can't string a zipline between two floors of the same building.