Final answer:
The number of custom summary formulas per report depends on the software's capabilities, and in the context of Salesforce reports, you can have up to 5 custom summary formulas.
Step-by-step explanation:
The question you are asking relates to the number of custom summary formulas allowed per report in a certain context, which is likely to pertain to a software application or a reporting tool. The options given are 1, 5, 10, and 25. Without a specific reference to the system or software being used, it's not possible to definitively answer this question. However, in many reporting systems, the number of custom summary formulas you can create is often limited by the software's capabilities or licensing terms.
If this question pertains to Salesforce reports, the correct answer is that you can have up to 5 custom summary formulas per report. Custom summary formulas are powerful tools that allow you to calculate additional totals based on the data in your report. You can use these formulas to analyze data that isn't directly provided by the report's standard fields. For example, if you wanted to calculate the average deal size or a weighted pipeline, you could use custom summary formulas to do so.