## Applied Statistics and Probability for Engineers, 6th Edition

$1$ to $491$
There are $500$ total parts, and $10$ do not work, so there are $490$ that do work. There are two extreme cases: 1) If the first part selected is a nonconforming part, then the random variable is $1$. 2) If every single conforming part is selected before the nonconforming parts, then the random variable is $490+1=491$. Thus the range is $1$ to $491$