A robot moving forward at a constant speed takes 2.5 hours to travel 1 kilometer. Moving forward at this same constant speed, it takes the robot 90 seconds to travel the length of a particular hallway. How many meters long is the hallway?
We see that 2.5 hours is the same as $2.5\cdot 60 = 150$ minutes, or $150\cdot 60 = 9000$ seconds.  This is 100 times longer than the robot was traveling the hallway, meaning the hallway is $\frac{1}{100}$ kilometers, or $\frac{1000}{100} = \boxed{10}$ meters long.