Final answer:
To obtain a standing, counted vote in a legislative body with thirty members present and twenty-five voting, a simple majority of at least 13 affirmative votes would be required.
Step-by-step explanation:
The question concerns the rule of majority voting within the context of a legislative body, where a member has requested a rising, counted vote following a voice vote on a main motion. With thirty members present and twenty-five casting votes, a majority would be required for a motion to pass. Majority rule typically requires more than 50% of the votes cast, which is usually defined as 50% + 1.
Since 25 members cast their votes, a simple majority would require at least 13 votes in the affirmative (which is 50% of 25, plus 1) for the motion to obtain a standing, counted vote. This is because the majority is calculated based on the number of votes cast, not the total number of members present.