How many minutes in a day ... are the sandwiches that exceed 15 sold? At least 20 salads were sold at the lunch stand.

The whole question is: on those days when at least 20 salads are sold, what percentage of the days when more than 15 sandwiches are sold at the same time?

The answer is D. 65438+7/02, only counting the points to the right of the vertical axis 20 and above the horizontal axis 15. Note that 15 or above does not include 15, so the points pasted on the horizontal line cannot be counted.