Final answer:
A Numeric filing system requires a cross-reference file to help locate specific files by providing an alphabetical list of names or subjects with their corresponding file numbers.
Step-by-step explanation:
The type of filing system that requires a cross-reference file is the Numeric filing system. In numeric filing systems, files are arranged by number rather than by name or subject. The challenge with this system is that it's not intuitive to remember the numbers associated with specific files, especially as the number of files grows. As a consequence, a cross-reference, or index, is crucial. This is an alphabetical list of names, subjects, or other categories along with their corresponding file numbers that allows you to swiftly locate the file number based on the name or subject you're looking for. Without a cross-reference in a numeric filing system, locating specific files can be time-consuming and cumbersome