Respuesta :

3/2000 is the answer 
A kilometer is 100,000 centimeters. 
150 out of 100,000 is 150/100,000. 
That is equal to 15/10,000. 
It's also equal to 3/2,000. 
That is as simplified as you can get. 
Side note: as a decimal it is 0.0015.
Hope this helps!