Answer:
The competitor will run 31,120 copies between service calls.
Step-by-step explanation:
We need to find a number of copies "n" whose value is the sum between itself and its 25 percent and this sum is equal to the 38,900 copies that the Brand X copier run between copies. We can do that by resolving the next equation:
[tex]n+0.25n=38900\\1.25n=38900\\(1.25/1.25)n=38900/1.25\\n=38900/1.25\\ n=31120\\[/tex]