In the parenthesis, we find the rate of increase or decrease of whatever is labeled, in this case, it is employees. In order to have an increase in rate, it must be a 1, or higher. In this problem it is lower, so the amount of employees are decreasing.
It is 10% decrease because 0.90 represents how many employees stay, while the rest away from 100 (10%) are decreasing in value, and we can figure that out by how many years and how many employees leave by plugging in a specific amount of years for <em>t. </em>
