1. The problem statement, all variables and given/known data The problem asks how many nanoseconds does it take for light to travel 1km in a vacuu? 2. Relevant equations I know that 1KM is equal to 1000 meters or 10^3. I also know that 1ns is equal to 10^-9s and light travels at about .3m per ns. 3. The attempt at a solution I'm not sure where to start with this problem. I know I have to convert the two givens but im stuck at where to start. I started to think that I could divide the .3m per ns by 10^9 and then multiply it by 10^3. If someone could help me figure out how to start this problem and a push in the right direction that would be highly appreciated. Thanx in advanced.