jmc

Question

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?

Accepted Answer

We see that 2.5 hours is the same as 2.5 60 = 150 minutes, or 150 60 = 9000 seconds. This is 100 times longer than the robot was traveling the hallway, meaning the hallway is 1100 kilometers, or 1000100 = 10 meters long.