To determine how long a marble takes to roll down a 5.0 m ramp at an angle of 6.9°, the correct answer is 2.9 seconds. The relevant equations include v = at and d = 1/2at², but the angle's effect on acceleration must be considered. The angle influences the time it takes for the marble to reach the bottom, as a steeper angle results in a shorter time. Participants in the discussion emphasize the importance of calculating the acceleration component down the ramp. Understanding the relationship between the ramp's angle and the marble's acceleration is crucial for solving the problem accurately.